Apply Credit memo to Invoice in 12.1.3 ?

Hi Experts ,

PO amount 10000

Invoice 10000

Payment 4000

Now user says he does not want to pay any more to the supplier and the remaining 6000 (for payment) should be as available balance in the budget .

We have encumbrance accounting setup .

                 Please suggest if applying a credit memo of 6000 to the invoice is going to solve the purpose as cancelling the invoice and payment is out of question (not acceptable)

for the user .

Best Regards

Nishikant