Confirm the request is genuine
Check it comes from an admin or the account owner, not an unknown sender.
Ask for the exact address
Get the full address and whether it replaces the old one or adds to it.
Update and send a test
Change the address and send a copy of the latest invoice to it.
Confirm in writing
Tell them what changed and which invoices will go to the new address.
Mention past invoices
Say whether earlier invoices can be resent on request.