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Project Management Service Agreement Addendum

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PROJECT MANAGEMENT SERVICE AGREEMENT ADDENDUM

This Addendum to the Project Management Service Agreement ("Addendum") is made effective as of between Client Name: and Service Provider Name: .

This Addendum modifies the Agreement dated for Project ID: . All capitalized terms not defined herein retain the meanings set forth in the Agreement.

Project Identification

Amendments to Agreement

The Agreement is hereby amended as follows. To the extent of any inconsistency between this Addendum and the Agreement, this Addendum shall control. All other terms of the Agreement remain in full force and effect.

Scope of Work

Deliverables and Acceptance

The following deliverables supplement those in the Agreement. Each deliverable must satisfy the acceptance criteria below prior to acceptance by Client.

Due Date:

Due Date:

Due Date:

Timeline & Milestones

Project Start Date:   Project End Date:

Milestone 1 Due:

Milestone 2 Due:

Budget, Fees & Payment

Change Order Process

All changes to scope, schedule, or fees under the Agreement must be documented in a written Change Order signed by authorized representatives of both parties prior to the commencement of work covered by the Change Order. No oral directions or informal emails shall constitute authorization for additional work or fees.

Acknowledgement:

Confidentiality

The parties reaffirm the confidentiality obligations in the Agreement. Each party shall protect Confidential Information of the other party with the same degree of care it uses to protect its own confidential information, but in no event less than reasonable care. Confidential Information shall not be used except for performance under the Agreement and this Addendum.

Duration of Confidentiality:

Acknowledgement:

Liability, Termination & Miscellaneous

Except as modified by this Addendum, the Agreement's limitation of liability, indemnity, and insurance provisions apply. Either party may terminate this Addendum for material breach of its terms following the notice and cure procedures set forth in the Agreement.

Notices to be sent to the addresses below. Notices shall be effective in accordance with the notice provisions of the Agreement.

Governing Law: This Addendum shall be governed by and construed in accordance with the laws of , without regard to its conflicts of laws principles.

Counterparts and Electronic Signatures: This Addendum may be executed in counterparts and by electronic signature, each of which shall be deemed an original and all of which together shall constitute one instrument.

Client Name:

By:

Date:

Service Provider Name:

By:

Date:

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What the Project Management Service Agreement Addendum Is

A Project Management Service Agreement Addendum is a short, written modification to an existing project management services contract that documents agreed changes without replacing the original agreement. Typical uses include scope adjustments, revised schedules, updated deliverables, budget or payment changes, and clarifications to acceptance criteria. The addendum should reference the original agreement by title and date, describe the change with specificity, set an effective date, identify responsible parties, and require signatures of authorized signers to become binding under the original contract terms and governing law.

Why Use a Formal Addendum for Project Changes

A written addendum preserves intent, prevents disputes, and documents authority for scope, schedule, or payment changes. It creates a clear record for invoicing, audits, and regulatory compliance, and makes amendment terms enforceable when properly executed by authorized signatories.

Why Use a Formal Addendum for Project Changes

Who Typically Prepares and Signs an Addendum

Several project stakeholders commonly draft, approve, or sign addenda depending on organizational structure and delegation of authority.

  • Project managers and PMO staff who identify and document scope or schedule changes for client and vendor review.
  • Vendor or contractor contract administrators who confirm revised deliverables, costs, and timelines for billing.
  • Client legal or procurement representatives who approve contract language and confirm budget or acceptance terms.

Use the addendum when the parties agree to a discrete change; avoid informal emails alone because they may lack the necessary execution, attribution, or retention to be enforceable.

Core Elements to Include in a Professional Addendum

A well-drafted addendum is concise but specific; it ties directly to the base agreement, identifies affected clauses, and sets clear acceptance criteria and timelines.

Reference

Cite the original agreement title, execution date, and specific clause numbers being modified to avoid ambiguity and support enforceability.

Scope Change

Describe added, removed, or revised tasks and deliverables in measurable terms, including technical specifications, milestones, and any exclusions.

Schedule

State new milestone dates, critical path adjustments, and any interim review or acceptance windows tied to payment triggers.

Compensation

Specify additional fees, payment schedule, invoicing instructions, and whether costs are fixed, time-and-materials, or capped.

Acceptance

Define testing, approval criteria, and remedy steps for rejected deliverables, including cure periods or rework obligations.

Dispute Terms

Confirm whether disputes follow the original agreement’s resolution process, governing law, and venue, or state any changes.

Required Administrative and Security Information

Party Legal Names: Full legal entity names only
Effective Date: MM/DD/YYYY format
Scope Identifier: Clause or exhibit reference
Payment Terms: Amount, due days, and method
Execution Evidence: Signed pages and audit trail
Access Controls: Role-based signer permissions

Step-by-Step: Completing the Addendum

Follow these ordered steps to prepare, approve, and execute the addendum with minimal friction and legal clarity.

  • 01
    Draft the Text: Record only the changes; avoid reprinting the whole contract to reduce inconsistency.
  • 02
    Cross-Reference: Cite original clause numbers, dates, and exhibits to anchor the amendment.
  • 03
    Obtain Approvals: Have authorized representatives review changes and confirm budget or scope acceptance.
  • 04
    Execute and Distribute: Collect signatures, add execution dates, and circulate final copies with an audit trail.

How to Configure the Online Workflow for an Addendum

Configure the digital signing sequence, authentication, and notifications before sending the addendum to stakeholders.

Template Save the addendum as a reusable template for similar future changes
Signer Roles Assign roles such as Client Signer, Vendor Signer, and Witness
Authentication Choose email link, SMS code, or higher verification methods
Conditional Fields Show payment fields only when compensation changes exist
Notifications Set reminders and final copy distribution addresses

Typical Submission and Signing Flow

A clear signing flow reduces delays and creates an auditable record of execution and distribution.

  • Upload Document: Attach the addendum and any referenced exhibits
  • Place Fields: Add signature, date, initials, and conditional numeric fields
  • Authenticate Signers: Use email link, SMS, or stronger identity checks as required
  • Finalize and Archive: Generate signed copies and a tamper-evident audit trail

Technical Requirements for eSigning and Delivery

Ensure the chosen eSignature platform supports authenticated signing, secure storage, and the file formats you use for contracts.

  • File Formats: PDF and DOCX are universally supported
  • Integrations: Link to CRM or ERP for automated contract tracking
  • Audit Trail: Capture timestamps, IP, and action history

Pick a solution that supports conditional fields, role-based access, and archival compliance so the executed addendum remains retrievable and defensible for audits or disputes.

Timing Considerations and Common Deadlines

Track the addendum’s effective date, notice deadlines, and any schedule impacts to avoid missed payments or milestone disputes.

Effective Date:

Determine whether the change is effective on signing or a later specified date

Notice Periods:

Honor any contract-required notice windows for scope or termination changes

Execution Deadline:

Set a signer deadline to prevent stale approvals

Implementation Window:

Define how soon work resumes under the new terms

Retention Start:

Record retention usually begins on the execution date

Common Mistakes to Avoid When Preparing an Addendum

  • Failing to reference the original agreement precisely, which can create ambiguity about which terms are amended.
  • Using vague or open-ended language for scope or deliverables that invites disputes over performance expectations.
  • Not confirming signatory authority, leading to later challenges about whether the amendment was binding.
  • Distributing unsigned drafts or relying on email approvals instead of obtaining clearly executed signatures and retention.

Key Risks and Consequences of an Incorrect Addendum

Invalid Amendment: May be unenforceable without proper signatures
Payment Disputes: Ambiguous compensation can delay invoices or trigger withholding
Schedule Exposure: Missed milestone dates can lead to liquidated damages
Regulatory Noncompliance: Healthcare or financial terms may breach HIPAA or other rules
Warranty Loss: Improper changes may void original warranty language
Audit Deficiencies: Poor retention undermines proof of agreed changes

Real-World Examples of Addendum Use

These examples show how organizations used executed addenda to document scope and integration changes alongside eSignature workflows.

Optica Ventures LLC

The firm used an addendum to extend an implementation schedule by two months and add QA milestones.

  • The change preserved original payment terms while adding milestone acceptance steps.
  • The interface is simple and easy-to-use for our team; more importantly, it is just as easy for our customers.

Xerox

Xerox applied an addendum to transfer approvals into NetSuite-driven workflows, tying amended invoices to signed deliverables.

  • Automated routing ensured synchronized accounting and project records.
  • airSlate SignNow provides us with the flexibility needed to get the right signatures on the right documents, in the right formats, based on our integration with NetSuite.

Who Is Typically Authorized to Sign

Project Manager — Authorized

The project manager may sign addenda when delegated authority exists in the original agreement or a corporate delegation of authority; ensure written evidence of delegation accompanies execution to avoid later challenges.

Client Representative — Authorized

A named client signing officer or procurement director normally executes amendments on behalf of the client; verify title and corporate authorization to confirm binding effect.

Key Milestones in the Amendment Lifecycle

Track milestone stages from proposal through implementation so responsibilities and timelines are clear to all parties.

01

Proposal Issued

Documented change request delivered to the counterparty for review

02

Review Window

Allocated period for legal, finance, and technical review

03

Execution

All authorized signers execute the addendum and date it

04

Implementation

Updated work begins per revised schedule and acceptance criteria

Typical eSignature Vendor Pricing and Feature Snapshot

Compare basic price and essential features for common eSignature providers to inform choices for signing and managing addenda. signNow is listed first per standard vendor comparison.

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 Yes, 7-day trial No No Yes, limited Yes, limited
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 envelopes/user/year Varies Varies Varies

Frequently Asked Questions and Troubleshooting

Answers to common legal, technical, and process questions about executing and managing a Project Management Service Agreement Addendum.


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