Identification
Reference the original contract, parties, and a unique change-order number for traceability and accounting.
A concise COS agreement reduces disputes, sets payment triggers, and documents agreed scope changes. It supports enforceability under ESIGN and UETA frameworks when signed electronically, and helps preserve audit evidence and timelines for performance and billing.
Contract managers, project managers, procurement officers, and outside counsel commonly prepare or review COS agreements before execution.
Ensure signatory authority is verified for each party before finalizing; unsigned or improperly signed COS agreements create collection and enforcement risk.
Reference the original contract, parties, and a unique change-order number for traceability and accounting.
Detailed deliverables, technical specifications, milestone descriptions, and any exclusions to avoid ambiguity.
Exact amounts or billing rates, payment triggers, timing, and invoicing instructions to prevent payment disputes.
Revised delivery dates, milestones, and any dependencies with remedies for missed deadlines.
Criteria and process for inspection, acceptance sign-off, and remedying defects post-delivery.
How further changes are requested, approved, and priced to avoid scope creep and preserve audit trails.
| Field | Configuration |
|---|---|
| Signer Order | Set sequential signing when approvals must follow internal steps |
| Authentication | Use email as baseline; require SMS or KBA for higher-risk deals |
| Audit Trail | Enable full event logging (IP, timestamp, actions) |
| Retention | Auto-archive signed PDFs and metadata in secure storage |
Ensure the chosen eSignature platform supports the integrations and compliance features your workflow requires.
Platforms with API and bulk-send options reduce manual work for high-volume COS processing and support automated archival in enterprise repositories.
Set internal sign-off windows (e.g., 5 business days) to avoid project delays
Define time allowed for inspection and formal acceptance
Specify when invoices are due after acceptance (net terms)
Follow retention timeline for executed agreements and supporting docs
Include short notification periods for defect claims
Project team documents the change and prepares draft change-order details.
Finance or procurement approves budget impact and payment terms.
Legal confirms contractual language and risk treatment.
Signatures collected, executed copy distributed, and files archived.
| Document Type | COS Agreement | Amendment | Purchase Order |
|---|---|---|---|
| Primary purpose | modify scope | change contract terms | order goods/services |
| Typical trigger | scope change | contract renegotiation | procurement request |
| Formality level | medium-high | high | low-medium |
| Accounting impact | adjusts sow billing | may reprice contract | new invoice line |
| 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 by vendor | Varies by vendor | Varies by vendor | Varies by vendor |
| Bulk Send | Yes | Yes | Yes | Yes | No |
| Audit Trail | Yes | Yes | Yes | Yes | Yes |
| HIPAA Compliant | Yes | Yes | Yes | No | No |