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Work started under one deal. A new contract does not quietly swap it.

The work is under way: brief agreed, start confirmed, first stage moving. Then a document arrives from the client's side, a standard contract, a vendor form, a procurement pack, and buried in it the payment terms are different from the ones you agreed: longer to pay, deposit gone, kill fees changed, payment tied to approvals nobody mentioned. It is presented as paperwork, a formality, just sign so the file is complete. Signing without comparing is how a good agreed deal gets replaced by a worse unsigned one at the exact moment you have the least leverage, with work already delivered into it. The rule is simple and calm: the job that started runs on the terms it started on, and nothing changes them except a written change both sides sign, naming what it replaces. Here is the comparison and the reply.

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Updated November 2, 2026. First published November 2, 2026. The two delivery records quoted below are real and public, with their client decision states read back from the live service on November 2, 2026.

Step 1. Do not sign on arrival, and do not stop the job in a panic either

Two reactions lose money here. Signing the same day because it looks routine converts your agreed terms into theirs at a stroke, possibly including work already done. Halting the job in outrage burns goodwill you may not need to burn, because half of these documents are genuinely thoughtless: a template their accounts side sends everyone, terms nobody at the client compared against your agreement. The steady move is a short holding reply, same day, in writing: received, I am comparing it against the terms we started under, the job continues on those terms meanwhile, and I will come back with any differences by a stated date. That one message does three things: it proves the document did not arrive and get silently accepted, it keeps the work and the relationship moving, and it puts a date on the comparison so the unsigned contract cannot hang over the job indefinitely.

Step 2. Compare the two sets of terms line by line, money terms first

Lay the agreed terms and the new document side by side and mark every difference, in this order. Payment timing: the days allowed, and what starts the clock, delivery, invoice, or their internal approval. The deposit and stage structure: amounts, when each stage is billed, and what releases the next one. Late payment: any fee, interest, or pause right the original carried that the new paper drops. Endings: cancellation and kill terms, what is owed for work done if the job stops, and who keeps what. Liability and ownership clauses that shift cost or rights in ways the price never reflected. And the signature trap itself: any line claiming this document replaces all prior agreements, because that line is the mechanism that would erase your terms even where the new document is silent. Produce the list as an actual list, numbers and dates, not an impression that the terms feel worse. The list is the negotiation; everything after this step is just sending it.

Step 3. Read the two states the started work can sit in while paper moves

A mid-job contract fight is won on whether the work already done sits under a record with its terms and acceptance attached, or inside a thread of goodwill. The record format is AER-1, published as an IETF Internet-Draft (draft-zambo-aer1-26), and each step carries a verifiable receipt: a receipt proves the saved result was not changed since it was saved. The two public records below show the states a delivery can carry:

Accepted: the decision is on the record

Pending: checked, and still waiting on a decision

An accepted record, 4 of 4 steps checked, decided_by client, release_hint ok_to_release, decided 2026-10-16T14:31:51.146Z in that example, fixes the early stages of a job exactly: delivered, checked, accepted, on the record that existed before the new contract arrived. Terms applied to that work are the terms it was performed under, and the record dates make the sequence plain to any third reader. A pending record, 5 of 5 steps checked and release_hint hold, is checked work awaiting its decision, and an unsigned contract with different terms is exactly the weather in which such a decision gets quietly re-decided on the new paper instead. Close the decision on the started stages under the original terms, in writing, before the contract conversation finishes.

Step 4. Send the differences back as a short, friendly, total reply

The reply carries the list from step 2 and one of three answers per item, nothing more dramatic. Acceptable as written, where the new wording changes nothing real. Already agreed differently, where the original term stands and you quote it with its source, the quote, proposal, or message both sides hold. Open to a change, priced or traded, where a longer payment wait might be acceptable against something real, a larger deposit, a firmer stage schedule, never conceded free and silently. Close the reply with the sentence the whole page exists to deliver: until both sides sign a change that names what it replaces, the work, including the work already done, runs on the terms it started under. Send it to the person who engaged you as well as to whoever sent the form, because template terms are often news to your actual client, and the person who wants the work done is your ally in getting their own template corrected.

Step 5. Know the shapes that are not templates, and answer those firmly

Sometimes the different terms are the point. Warning shapes: payment stretched far beyond the agreed days with no trade offered; the deposit removed after it was the reason you started; payment made conditional on a third party's approval or on the client's own client paying them; a clause signing away the right to pause on non-payment; the document backdated, or pressed for signature with the work held up until it is signed. Any one of these converts the reply from a comparison into a boundary: the original terms stand, new stages do not start until the paper matches them or a signed change both sides chose replaces them, and work already done is invoiced under the original deal. Delivered firmly and early, that boundary usually produces the corrected document, because a client who needs the work has no interest in losing the supplier over their own form. Delivered late, after stages have piled up unsigned, it produces an argument about leverage instead of a correction of paper.

Step 6. Start the next job with the paper finished before the work is

The durable fix is sequencing. The agreement, with the payment terms stated in numbers, signed or confirmed in writing before the start date, and the sentence that closes the mid-job swap: no later document changes these terms for this engagement unless a written change signed by both sides names the term it replaces. Large clients with real procurement can still be served inside that rule: their vendor process runs in parallel before the start, or the first stage is small and paid on your terms while their paper catches up, and if their process cannot move first, the start date moves, pleasantly and in writing. What the rule abolishes is the ambush shape, terms renegotiated by envelope after your leverage has been spent into the work. Paper first is not bureaucracy. It is the cheapest clause you will ever write.

What a record does not settle

A verifiable receipt proves the saved result was not changed since it was saved; it does not interpret a contract, decide which document governs a dispute, or replace advice on a real signing decision. The original agreement, the dated record of work started and accepted under it, the new document, and your written comparison are what the conversation stands on. This page is general information, not legal advice, and a contract with real money at stake deserves a lawyer's read before a signature.

Frequently asked questions

My client sent me a contract with different payment terms after the work already started. What do I do?

Do not sign it on arrival and do not treat it as the deal. Send a same-day holding note: received, comparing it against the terms the work started under, job continues on those terms meanwhile, differences back by a stated date. Then compare line by line, money first: payment days and what starts the clock, deposit and stage structure, late payment terms, cancellation and kill terms, and any clause claiming the document replaces all prior agreements. Reply with the differences listed in numbers, each marked acceptable, already agreed differently with the original term quoted, or open to a traded change, and close with the governing sentence: until both sides sign a change naming what it replaces, all the work, done and to come, runs on the original terms. Half of these documents are unexamined templates and get corrected. The other half are answered by the same list, delivered early, while your position is strong.

They say it is just their standard paperwork and everyone signs it. Is that true?

Often it is genuinely standard, and that fact changes nothing about the comparison. Standard paperwork is written to protect the sender's standard interests: longer payment clocks, approvals on their side, no deposits. Your agreed terms were written for this engagement. Where the two do not conflict, sign happily and file it. Where they do conflict, standard is a description of the document, not an answer to a difference, and the courteous reply stays the same: here are the four places it departs from what we agreed, here is what we agreed, please issue the corrected version or confirm in writing that the agreed terms govern where they differ. Companies correct their own templates for valued suppliers every week. What they cannot do is correct a difference nobody listed, which is why the list, not the sentiment, is the reply.

I already signed it. Is the original deal gone?

Not automatically, and this is exactly where real advice matters, but your position is far from hopeless and the record does the heavy lifting. Gather the sequence in dates: the original agreement and its terms, the work started and any stages delivered and accepted under it, the date the new document arrived and was signed, and any messages showing what each side understood it to be. Work already performed was performed under the original deal, and documents that replace agreements usually say what they replace and from when, which is why reading the replacement clause itself comes first. Raise the differences in writing now rather than at invoice time, because a prompt, good-faith correction request reads very differently from a surprise at payment. Then take the set to a lawyer if the sums justify it; an hour of advice on a signed discrepancy is cheap against a stretched payment clock on a whole engagement.

Should I pause the work until the paper is sorted?

Pause the exposure, not necessarily the work. Stages already agreed and under way can finish, because finishing them under the original terms grows a completed, acceptable record rather than a half-done one. What does not start is new scope, new stages, and any deliverable whose release your original terms tied to a payment the new paper has moved. Say exactly that in the holding reply, with the date your comparison lands, so the pause has a shape and an end. If the differences turn out to be template drift, the job never actually stopped. If they turn out to be deliberate, you stopped at the last point where the original deal fully covered you, and every hour since then is hours you did not donate to a renegotiation conducted by envelope.

How do I start the next job so terms cannot be swapped mid-job?

Finish the paper before the work and fix each engagement on a record. The agreement states the payment terms in numbers and carries the line that no later document changes them without a written change, signed by both sides, naming the term it replaces. When the work then runs through Zambo, every step carries a verifiable receipt under AER-1, published as IETF Internet-Draft draft-zambo-aer1-26, so what was started, delivered, and accepted, and when, sits on one dated record that any later document has to reckon with. New users get 20 calls and 1 wrap-up free every day, and picking up work in another AI is always free. For $0.99, start the next engagement that way and let the record hold the sequence: get the Day Pass. A Day Pass is unlimited for 24 hours, no subscription. Ongoing use is the Zambo Pass at $29 a month or $290 a year, and $19 a month for $ZAMBO holders, which adds private handover links, your branding, and the approval record as PDF and JSON files.

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