Copilot gave you a formula. Did the workbook actually change?

Confirm whether you are asking or editing

Microsoft's current Excel guidance distinguishes editing, planning and chat modes. Editing can make changes directly in the workbook; chat can discuss the workbook without changing it. Availability varies with subscription, platform and organisational settings.

Look at the mode and the actual file before judging the result. If the assistant provides a formula in its response, establish whether it inserted that formula or merely proposed it. Do not infer an edit from confident wording.

Be specific about the final output

If the job ends with an email explaining a correction, carry the checked findings into that next step. Explain what actually changed and what remains uncertain. Inspect the draft in the destination application; text in chat is not necessarily a saved email draft.

If the job ends with a management pack, review the exported page or file that management will see. A corrected working sheet and a stale PDF can coexist. Check both before saying the update is complete.

Know when to stop

• The intended file was changed, not just described.
• The calculation and business meaning were checked.
• Dependent outputs agree with the corrected data.
• The saved or exported result was opened and reviewed.
• The person receiving it can see what changed and what remains unresolved.