1. If no amount is paid for the invoice, refer to the article How do I change the vendor on an Accounts Payable invoice?
2. If the invoice is partially paid, refer to the article How do I write off the balance of a partially paid invoice in Accounts Payable?
3. Enter a new invoice on the new vendor.

For more information about changing the vendor name, refer to the article How do I change an Accounts Payable vendor name when their business name changes?"