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Professional Services Agreement Addendum

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PROFESSIONAL SERVICES AGREEMENT ADDENDUM

This Addendum to the Professional Services Agreement (the "Addendum") is made as of by and between Service Provider Name: and Client Name: .

RECITALS

WHEREAS, the parties entered into a Professional Services Agreement titled dated (the "Agreement");

WHEREAS, the parties desire to amend certain terms of the Agreement as set forth in this Addendum in order to reflect changes to the scope of work, compensation, and related provisions; and

WHEREAS, except as expressly amended by this Addendum, all terms and conditions of the Agreement remain in full force and effect.

NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are acknowledged, the parties agree as follows:

1. AMENDMENT TO SCOPE OF SERVICES

The Scope of Services described in the Agreement is amended as follows. The Service Provider shall perform the additional and modified services set forth below and shall comply with the performance standards and milestones specified.

2. COMPENSATION AND PAYMENT

The parties agree that the compensation terms set forth in the Agreement are amended as follows. All fees are exclusive of taxes unless otherwise required by law.

3. TERM; TERMINATION

The term of the Agreement is amended to continue until unless earlier terminated in accordance with the Agreement. Either party may terminate this Agreement in accordance with the termination provisions set forth in the Agreement; provided, however, that for terminations based on convenience, the terminating party shall provide days' prior written notice.

4. REPRESENTATIONS; WARRANTIES

Each party represents and warrants that it has the full power and authority to enter into this Addendum and to perform its obligations hereunder. Service Provider further represents that the services will be performed in a professional and workmanlike manner consistent with industry standards.

5. CONFIDENTIALITY

All Confidential Information, as that term is defined in the Agreement, shall remain subject to the confidentiality obligations of the Agreement. No disclosure or use of Confidential Information is permitted except as expressly allowed by the Agreement or as required by law.

6. INDEMNIFICATION; INSURANCE

The indemnification obligations in the Agreement shall apply to claims arising from the performance of the amended services. Service Provider shall maintain insurance coverage consistent with the requirements of the Agreement and provide certificates of insurance upon request.

7. NOTICES

All notices required or permitted under this Addendum shall be given in writing and delivered in accordance with the Agreement. The parties' notice addresses for purposes of this Addendum are as follows:

8. CONFLICT; INCORPORATION

In the event of any conflict between the terms of this Addendum and the Agreement, the terms of this Addendum shall govern solely with respect to the subject matter hereof. All other provisions of the Agreement are incorporated by reference and remain unchanged and in full force and effect.

9. AMENDMENTS; WAIVER

This Addendum may not be modified or amended except by a writing signed by duly authorized representatives of both parties. No waiver of any term shall be effective unless in writing and signed by the waiving party.

10. GOVERNING LAW; VENUE

This Addendum shall be governed by and construed in accordance with the laws of the state of without regard to principles of conflicts of law. The parties submit to the exclusive jurisdiction of the courts located in that state for disputes arising under this Addendum.

11. ENTIRE AGREEMENT; SEVERABILITY

This Addendum, together with the Agreement, constitutes the entire agreement between the parties with respect to the subject matter hereof and supersedes all prior and contemporaneous agreements, understandings and communications, whether written or oral. If any provision of this Addendum is held invalid or unenforceable, the remaining provisions shall remain in full force and effect.

12. COUNTERPARTS; EXECUTION

This Addendum may be executed in counterparts, each of which shall be deemed an original and all of which together shall constitute one and the same instrument. Signatures delivered by electronic means shall be effective as original signatures.

IN WITNESS WHEREOF, the parties have caused this Addendum to be executed by their duly authorized representatives as of the date first written above.

Service Provider:

Printed Name:

By:

Date:

Client:

Printed Name:

By:

Date:

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What the Professional Services Agreement Addendum Is

A Professional Services Agreement Addendum is a written amendment to an existing services contract that records agreed changes to scope, schedule, fees, deliverables, or other material terms. It operates alongside the original Professional Services Agreement and only modifies the specific provisions identified. Addenda are used to document negotiated changes without replacing the base agreement, to confirm mutual consent to revisions, and to create an auditable record for procurement, billing, and compliance purposes. When signed by authorized parties the addendum becomes binding; electronic signatures are valid under federal ESIGN and applicable state law when the parties meet intent, consent, attribution, and retention requirements.

Why an Addendum Matters for Service Contracts

An addendum provides a clear, limited record of change that reduces disputes, aligns expectations, and preserves the original contract’s remaining terms. It supports project governance and auditability while documenting mutual acceptance of altered obligations.

Why an Addendum Matters for Service Contracts

Who Typically Prepares and Signs a Services Addendum

Various stakeholders prepare or approve addenda depending on organizational structure and contract value.

  • Service providers and account managers — prepare changes to scope, schedule, and pricing after client approval.
  • Client procurement or project managers — review proposed revisions and confirm operational impact and budget alignment.
  • In-house counsel or contracting officers — verify that the addendum preserves required warranties, indemnities, and governing law clauses.

Ensure the person creating the addendum coordinates with legal, procurement, and the authorized signer to avoid invalid or unauthorized modifications.

Core Components Every Addendum Should Include

A well-structured addendum identifies the original agreement, states the effective date, and clearly lists each amendment with precise cross-references so parties, auditors, and implementers can apply changes without ambiguity.

Reference

Cite the original Professional Services Agreement by title, date, and contract number so the amendment attaches unambiguously to the correct base agreement.

Effective Date

Specify the effective date of the changes using MM/DD/YYYY format and whether changes apply retroactively or prospectively.

Scope Changes

Describe additions, deletions, or modifications to deliverables, tasks, or services with measurable acceptance criteria and updated milestones.

Fees & Payment

List new fees, billing schedules, rates, or one-time adjustments and tie them to invoicing and payment terms already in the base agreement.

Terms Preserved

State that all other terms of the original agreement remain in full force except as expressly modified by this addendum.

Authority & Signatures

Include printed names, titles, signature blocks, and a statement that signatories have authority to bind their organizations.

Essential Data Fields to Capture

Party Names: Full legal names
Contract Reference: Original agreement ID
Effective Date: MM/DD/YYYY
Amendment Details: Clear change summary
Signatures: Signed and dated
Governing Law: Designated jurisdiction

Step-by-Step: Completing an Addendum

Follow these steps to prepare, approve, and execute a Professional Services Agreement Addendum consistently and securely.

  • 01
    Draft Changes: List specific clauses to change and updated language.
  • 02
    Internal Review: Have legal and procurement verify terms and risks.
  • 03
    Obtain Approvals: Get sign-off from budget and project owners.
  • 04
    Execute: Collect signatures and distribute executed copies.

Setting Up an Online Addendum Workflow

Configure templates, authentication, and routing to speed completion while preserving compliance and audit trails.

Field Configuration
Template Upload Upload DOCX or PDF and lock base clauses.
Conditional Fields Show payment fields only when fees change.
Signer Order Set sequential or parallel signing as required.
Authentication Use email, SMS, or stronger verification.

Where to Send or File the Executed Addendum

After execution, route copies to internal and external stakeholders to complete billing, project, and compliance workflows.

  • Client Records: Send executed PDF to client contract repository.
  • Internal Legal: Deliver signed copy for contract management.
  • Project Team: Provide updated scope and milestone details.
  • Accounting: Upload for invoice adjustment and audit trail.

Digital Signing and File Format Requirements

Ensure your e-signature platform supports required formats, authentication, and an auditable certificate of completion.

  • File Formats: PDF or DOCX supported
  • Integrations: Connects with CRM and cloud storage
  • Authentication: Email, SMS, or higher verification

Typical Timeframes and Deadlines to Track

Track key dates for when changes take effect, notice windows, invoicing, and internal approval deadlines to avoid service gaps or billing disputes.

Effective Date Specification:

Specify whether changes are effective on signing or a stated future date.

Notice Periods:

Honor any contractual notice periods for scope or fee changes (commonly 30 days).

Invoice Adjustments:

Submit amended invoices within the contract’s billing cycle after execution.

Retention Start:

Record retention begins on effective date or signature date.

Approval SLA:

Set internal approval turnaround (example: 5–10 business days).

Common Preparation Mistakes to Avoid

  • Vague scope edits that lack measurable deliverables, causing later disputes and scope creep.
  • Failing to reference the original contract precisely, creating ambiguity about which document the addendum modifies.
  • Missing or unsigned signature blocks for an authorized representative, which can render the addendum unenforceable.
  • Not updating invoicing or accounting systems after fee changes, leading to payment delays or incorrect billing.

Risks and Legal Consequences of Defective Addenda

Unenforceability: Court may refuse to enforce
Tax Reporting: Incorrect reporting or withholding
HIPAA Exposure: Unauthorized PHI disclosures risk penalties
Breach Claims: Disputed obligations and damages
Contract Defaults: Failure to satisfy notice provisions
Procurement Violations: Non-compliance with purchasing rules

eSignature Vendor Pricing and Feature Snapshot

Below is a concise comparison of starting prices and feature availability for commonly used eSignature providers; signNow is listed first per platform comparison conventions.

signNow DocuSign Adobe Sign PandaDoc HelloSign
Starting Price $8/user/mo $15/user/mo $14/user/mo $19/user/mo $15/user/mo
Free Trial 7-day free trial Varies Varies Varies Varies
Bulk Send Yes Yes Yes Yes No
Audit Trail Yes Yes Yes Yes Yes
HIPAA Compliant Yes Yes Yes No No
Envelope Cap No cap 100 env/user/yr Varies by plan Varies by plan Varies by plan

Real-World Examples of Addendum Use

These condensed examples show how organizations document contract changes and realize governance benefits from clear amendments.

Optica Ventures

The team needed a scope increase for software services after a change request was approved.

  • The addendum detailed new deliverables and payment schedule.
  • After execution the project team updated milestones and billing immediately, preventing invoice disputes and maintaining client satisfaction with a clear change record.

Xerox

A systems integration project required an extra integration module and extended timeline.

  • The addendum attached an exhibit with acceptance tests.
  • Executing the amendment aligned procurement, accounting, and operations, enabling automated invoice adjustments and eliminating ambiguity about acceptance criteria.

Who Typically Signs and Why Their Role Matters

Service Provider

The provider’s authorized signatory—often a director of operations or contracting manager—signs to accept modified deliverables and payment terms, ensuring the company is contractually bound to perform the amended work.

Client Representative

A client’s procurement officer or project sponsor signs to confirm budget approval and acceptance of changes; their signature commits the organization to pay under the revised terms and triggers internal implementation.

FAQs: Enforceability, Signing, and Common Issues

Answers to frequent questions about validity, electronic execution, and practical next steps when problems arise.


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