Change order vs contract amendment
Both documents change a contract that's already signed. A change order adjusts the work: what gets built, what it costs, when it's done. A contract amendment changes the deal itself: payment terms, warranties, who the parties are, how disputes get settled. Pick the wrong one and you can end up with a price change nobody agreed to properly, or terms that were never really changed.
Updated October 13, 2026 · 4 min read
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What a change order does
A change order works inside the contract you already have. Most construction and service contracts include a changes clause that says how the scope can be adjusted and how the price and schedule move with it. A change order uses that process. The terms stay the same; the work, price or finish date changes.
Change orders are frequent and small. A remodel can collect several: an upgraded tile, a moved outlet, a repair to something found behind a wall. Each one is usually a page.
What a contract amendment does
An amendment rewrites part of the contract itself. You'd use one to change the payment schedule, extend a warranty, add or swap a party, change the termination terms, or fix a mistake in the original language. Amendments are less common, they tend to go through more review, and they usually follow whatever amendment clause the original contract sets out.
Side by side
| Change order | Contract amendment | |
|---|---|---|
| What changes | Scope, price, schedule | The contract's terms and conditions |
| Works through | The contract's changes clause | The contract's amendment clause, or a new agreement between the parties |
| How often | Often, sometimes several per job | Rarely |
| Typical length | One page | As long as the terms it changes |
| Who usually drafts it | The contractor or service provider | Either party, often with a lawyer for big changes |
| Example | Add a second bathroom fan, plus a day to the schedule | Switch from three payments to monthly billing |
Which one do you need?
- More or less work, a substitute material, a new finish date: change order.
- A new payment schedule, warranty, cancellation term or party: amendment.
- A big expansion that changes the whole job: often both, or a new contract. If the new work dwarfs the old, a fresh contract can be cleaner than stacking changes.
- Not sure: read the original contract's changes and amendment clauses. They usually say which form a given change has to take.
State rules can apply to change orders
Some states regulate change orders on consumer contracts. In California, for example, a home improvement change order isn't enforceable against the homeowner unless it states the scope, the amount added or subtracted, and the effect on payments or the completion date.
What both should include
- A clear reference to the original contract: its date, the parties and the job or account.
- Exactly what's changing, in plain language, and what stays the same.
- The effective date.
- Any change to price, payment timing or schedule, with the new totals.
- Signatures from people with authority to bind each party.
- A signed copy for everyone who signed the original.
Our guide to writing a change order has a one-page structure you can copy.
Keep a change log
On a job with more than a couple of changes, keep a simple running list: change order number, date, a one-line description, the amount, days added, and whether it's signed. It takes a minute per change and saves an hour at the end.
- It reconciles the final bill. Original contract amount plus every signed change order should equal what you invoice.
- It catches gaps. A missing number in the sequence is a change someone forgot to sign or bill.
- It shows the history. If a dispute comes up, you can show every approved change in order, each with its own signature.
Keep amendments in the same file as the contract they change, so anyone reading the contract later knows which terms still apply.
Related documents you might hear about
- Addendum: extra terms or pages attached to a contract, often at signing, that become part of it.
- Rider: a short add-on that changes or adds coverage, common in insurance and leases.
- Scope of work: the description of the job inside the original contract. Change orders adjust it. See scope of work.
Signing either one electronically
Under the federal ESIGN Act and state UETA laws, a contract or signature can't be denied legal effect just because it's electronic, and that includes changes to an existing contract. If the original contract says changes must be made a certain way, follow it.
With SignMaster you can keep a template for each: a one-page change order with fields for the description, amount and new total, and an amendment with fields for the effective date and signatures. Send either from your phone, or hand your phone over and use Sign in person. Each send is an envelope: SignMaster's word for one or more documents going to one or more signers. An envelope can hold several documents, so the amendment can travel with the original contract for reference. Everyone gets the signed PDF and a certificate of completion when the last person signs.
Questions? Answers.
Is a change order legally binding?
A change order signed by both parties is generally as binding as the contract it changes, as long as it follows the contract's changes clause and any state rules. Unsigned or verbal changes are much harder to enforce.
Can a change order change the contract price?
Yes. Adjusting price along with scope is one of its main jobs. Show the previous total, the change and the new total.
Who needs to sign an amendment?
Usually the same parties who signed the original contract, or people with authority to act for them. Check the original contract's amendment clause, which often says changes must be in writing and signed by both sides.
What's the difference between an addendum and an amendment?
An addendum usually adds terms or pages, often at signing. An amendment changes terms that are already in a signed contract. In practice people mix the words up, so read what the document actually does.
Sources
- California Business and Professions Code § 7159.6, extra work and change orders · leginfo.legislature.ca.gov
- 15 U.S.C. § 7001, ESIGN Act general rule and consumer consent (govinfo) · govinfo.gov
- Uniform Electronic Transactions Act (1999), final text (Uniform Law Commission) · uniformlaws.org
General information, not legal advice. Laws change, and how they apply depends on your situation. For advice about a specific document, talk to a lawyer licensed in your state.