Final answer:
To journalize the issuance of a note to convert an account payable, you debit Accounts Payable and credit Notes Payable, reflecting a change in the form of the liability.
Step-by-step explanation:
The entry to journalize the issuance of a note to convert an existing account payable would be debit Accounts Payable and credit Notes Payable. This entry reflects the replacement of the liability from an open account payable to a formal promise to pay represented by a note. When a company issues a note payable to settle an account payable, the liability is not eliminated, but it's rather transformed into a new instrument with potentially different payment terms and possibly interest.