Unfortunately, debit and credit memos are unable to be deleted. However, you are able to offset each of them! To offset a debit memo, we recommend issuing a credit memo for the same amount as the debit memo. To offset a credit memo, we recommend issuing a debit memo for the same amount as the credit memo.
Additional information on Credit and Debit memos can be found here.
Note: When issuing a debit memo, it will require you to select a disbursement method. Unless paying out an account balance to the customer by check, we recommend using cash as the disbursement method.