My client wants me to sign a new contract before paying an old invoice. What should I check?

You completed the project and sent the invoice. Instead of payment, the client sends a fresh contract: “Finance needs this signed before we can process anything.”

Sometimes the missing document records details both sides already intended. Sometimes it asks you to accept new conditions after the work is done. Read it as a proposal, not as an administrative formality.

Make two columns before reading clauses

Start with the transaction history.

The label “vendor onboarding” does not tell you what the words do. A tax form and bank-details form are different from a contract that rewrites the deal.

Search for the clauses that can reach backwards

Pay particular attention to:

• an effective date earlier than the signature date;
• wording covering “all services provided” or earlier deliverables;
• a statement that the new document is the entire agreement;
• a release, waiver or “full and final settlement”;
• payment being conditional on a purchase order, timesheet or acceptance not previously required;
• ownership transferring before or regardless of payment;
• warranties, indemnities or liability applying to work already completed;
• a right for the client to deduct, set off or withhold amounts.

Also compare party names. If the original work was ordered by one company but the new agreement names an affiliate, ask who owes the invoice and why the entity changed.

Use a change map, not a general objection

For each relevant passage, write:

These are fictional examples. Their legal effect depends on the complete documents and applicable law. The point is to identify the exact change instead of responding, “I don’t like the contract.”

Ask why signature and payment are linked

Try a precise response:

I’m happy to complete the information Finance needs. Before signing, please clarify how this document relates to the project ordered on [date] and invoice [number]. The work was completed under [proposal/email/agreement], with payment due on [date]. The new document appears to apply from an earlier date and includes new acceptance, ownership and release terms. Please confirm that payment of invoice [number] is not conditional on accepting new terms for completed work, or send a version that expressly excludes that work and invoice.

Save the request, the document version and the response. Do not change the document yourself and assume the other side accepted your edits.

Keep the payment question moving

Continue following the original agreement’s invoice and notice process. If part of the amount is genuinely disputed, ask the client to identify that part and its basis rather than leaving the whole invoice undefined.

Rights and remedies vary by place and relationship. For example, the UK has statutory rules and official guidance on some late commercial payments, but that page does not decide who owes your particular invoice or whether the new document is effective. Local freelance-payment laws may also apply; New York City’s freelance worker guidance is one jurisdiction-specific example.

If the client’s explanation is instead “we will pay when our customer pays,” use the payment-chain checklist. The central discipline is the same: connect the demand to the agreement that actually governed the work.