Apply Credit Memo against an invoice via Create New Payment Page:
a. When Credit Memo amount = Invoice open amount: No Payment will be created, only application of Credit memo against Invoice.
b. When Credit Memo amount < Invoice open amount: Payment will be created for the difference + application of credit memo against the invoice. (Credit Memo = Fully Applied).
Deleting Payment record will just delete the payment but not remove the application of Credit Memo from the invoice.
1. After deleting payment > Pull up Credit Memo.
2. Hit Edit.
3. Under Items tab > Apply subtab > remove check mark on Apply check box.
4. Hit Save.
This will make the credit memo available again and status will now be ''Open''.