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Key takeaways
- A contract amendment is a written change to the terms of an existing contract, signed by the parties.
- It should identify the original contract, state exactly what changes and say that everything else stays as it was.
- An amendment changes terms. A change order changes scope, price or schedule within the terms.
- Follow the contract's own rules on how amendments must be made, such as a writing signed by both sides.
Free PDF and Excel: Contract amendment template and checklist. Get it below
What a contract amendment is
A contract amendment is a written document that changes one or more terms of an existing contract, agreed and signed by the parties to that contract.
Contracts often say that changes must be in writing and signed by both sides. That clause is why an email thread or a casual agreement may not be enough. If you want a change to bind, put it in an amendment that follows the contract's own rule for amendments.
A supplier and a buyer agree by phone to extend a supply contract by six months and raise the unit price by 3 percent. The contract says amendments need a signed writing. Nothing is signed.
When the buyer later refuses the increase, the supplier has no signed document. An amendment signed in March would have settled it.
What to include
| Field | What goes in it | Why it matters |
|---|---|---|
| Title and number | Amendment No. 1 to the agreement. | Orders amendments in sequence. |
| Parties | Same as the original. | Identifies who is bound. |
| Original contract | Title and date of the agreement. | Ties the amendment to the right contract. |
| Changes | Exact clause numbers and the replacement wording. | Removes doubt. |
| Effective date | When the change starts. | Avoids retrospective arguments. |
| Everything else unchanged | A statement that other terms remain in force. | Prevents accidental changes. |
| Signatures | Authorised signatories and dates. | Makes it binding. |
Free PDF and Excel
Contract amendment template and checklist
An amendment outline with clause-level wording, a checklist and a log of all amendments to a contract.
- Amendment outline
- Pre-signing checklist
- Amendment log
- Excel contract change log
Amendment, addendum, change order
| Document | Changes | Example |
|---|---|---|
| Contract amendment | Terms of the contract | Extend the term, change payment terms |
| Addendum | Adds new terms or attachments | Add a data protection schedule |
| Change order | Scope, price or schedule within the terms | Add six extra data points to a job |
See change order for scope changes, statement of work for project terms and master service agreement for the framework they sit under.
Mistakes
- Relying on emails when the contract requires a signed writing.
- Amending the wrong version of the contract.
- Vague wording such as "adjust the price accordingly".
- Signed by someone without authority.
- No record of how the amendment fits with earlier ones.
- Original contract and date are cited.
- Clause numbers and new wording are exact.
- Effective date is stated.
- Everything else is confirmed as unchanged.
- Signatories have authority.
- The amendment is filed with the contract.
Last checked: 19 October 2026. General contracting practice. This is not legal advice. Have counsel review significant amendments.
Frequently asked questions
What is a contract amendment?
A written change to the terms of an existing contract, signed by the parties.
Does an amendment need to be signed?
If the contract requires it, yes. Even if not, a signed amendment is far better evidence.
What is the difference between an amendment and an addendum?
An amendment changes existing terms. An addendum adds new terms or documents. The words are often used interchangeably.
Can an email amend a contract?
Only if the contract and the law allow it. Many contracts require a signed document.
How should amendments be numbered?
Sequentially, such as Amendment No. 1 and No. 2, and keep a version log.