If you can't delete a sales credit note, you can create and allocate a sales invoice to reverse it.
If your invoice has transactions allocated to it, unallocate the credit note from the invoice first.
You can't delete a sales credit note if:
If you included the credit on a submitted VAT Return, reverse it after removing any allocations.
Reversing a credit note creates an opposing transaction. This transaction cancels the original credit note. This transaction:
The invoice and credit note now cancel each other out. You can now recreate the credit note if required.
Delete a refund allocated to a credit note