Change order
A short signed amendment that records a change to the agreed scope and what it does to the fee and the dates.
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What it is
A change order is a short signed amendment that records a change to a contract already in flight and what it does to the money, the dates, and any other affected terms. Adding work is the common case, but a change order can just as easily remove a deliverable, swap one thing for another, or move a deadline with no fee attached. The term comes from construction, where 'while you're here, can you move that wall' has always had a price attached, and it transfers cleanly to design and software work.
Reach for it the moment a request changes the deliverables in your SOW in either direction. Four lines are enough: description of the change, the fee adjustment (up, down, or none), new dates for the affected milestones, and a signature line. Keep it boring and one page. The point is not legal armor, it is making the cost of a request visible at the moment the request is made, while the client still wants the thing badly enough to pay for it.
Gotcha: starting the work before the signature comes back. Once the change is built, you have no leverage and the client has no reason to sign. Second gotcha: comping the first three small ones as goodwill teaches everyone that change orders are optional, so the fourth one reads as you suddenly getting difficult about money.
Ask AI for it
Write a one-page change order for the request described below, as an amendment to an existing signed SOW. Include: reference to the original SOW and date, a plain-language description of what changes (work added, removed, or substituted), what stays unchanged, the fee adjustment with how it was calculated, the revised milestone dates including any knock-on delay to later deliverables, a validity window for the price, and signature blocks for both parties. Add a line stating work on this change begins only after both signatures. Friendly and factual, no legalese, no apology.