A change order is a written amendment to a construction contract that documents a change to the scope, price, or schedule of a job — signed by both the contractor and the client before the added work happens.
Every construction contract describes a fixed scope of work for a fixed price. The moment anything about that scope changes — a client wants an upgrade, you hit something unexpected behind a wall, a material runs out — the original contract no longer covers what's actually happening on the job. A change order is the document that captures the difference: what changed, what it costs, how it affects the timeline, and confirmation from both sides that they agree.
It doesn't replace the contract. It attaches to it, the same way an amendment attaches to any legal agreement, and becomes part of the record of what was actually agreed to build.
Without one, the only record of a scope change is a conversation — and conversations get remembered differently by the two people who had them. A change order protects the contractor by creating a clear, signed basis for billing added work, and it protects the client by making sure they know the cost and schedule impact before they're committed to it. Skipping this step is the single most common way contractors end up doing extra work for free.
At minimum: who the parties are and which job/contract this attaches to, a clear description of the change, an itemized cost breakdown, the schedule impact, and signature lines for both the contractor and the client. For the full field-by-field list, see the change order form guide, or grab the ready-to-use change order template.
A verbal “yeah, go ahead” on-site feels like an agreement, and often is one — but it isn't a change order until it's written down and signed. Most contracts require this explicitly, and even when they don't, an unsigned change leaves you with no clean way to bill for it or resolve a disagreement about price later. The gap between the verbal “yes” and the signed paperwork is exactly where change orders traditionally get lost — which is the reason to get it signed on the spot, before you leave the job site.
This page is general information, not legal advice. Contract language varies by state and by job — for anything unusual or high-value, have an attorney review your process.
It can be, but it's hard to prove and easy to dispute. Most construction contracts explicitly require changes to be in writing and signed by both parties to be enforceable — even if the client agreed out loud on-site. Get it in writing before the added work starts.
The contractor (or an authorized representative) and the client or property owner. On commercial jobs, an architect or owner's rep may also need to sign off depending on the contract.
Don't start the added work. An unsigned change order isn't enforceable, which means you may not get paid for it and the client can dispute the cost later. If a client is asking for something but won't sign, treat that as a conversation to have before you touch the job, not after.
No. A change order is an amendment — it modifies specific terms (usually scope, price, and schedule) while the rest of the original contract stays in force.