Partial credit memo is still unapplied

We have an old credit memo that (for some reason) was not completely applied to outstanding invoices. We cannot delete the unapplied portion of the credit memo unless we unapply it from all invoices. I assume if we did that, we would need to re-enter the credit memo in two pieces…one part for the amount we did apply to invoices and the other part for the amount we never applied to anything. Then I assume we could delete the unused portion of the credit memo. Is that what we have to do to get this deleted from the system entirely? Is there no option to post a debit memo or a negative credit memo and apply the unused portion to that? It's always going to be a reconciling item on my reconciliation of A/P to GL if I can't delete it or apply it to something. We can't apply it to an invoice at this point because we no longer use this vendor.