Move a pre payment to a different customer account.

SUGGESTED

We had a customer who made a prepayment for an order. I posted the prepayment in cash receipts entry and that all went fine.

My issue is that the customer asked to change the account the order is under, this was after the prepayment was already posted to the original account. I can't figure out to move the prepayment from the incorrect customer account other new one. I was thinking of just re posting the payment to the correct account, but wouldn't that just add money in twice to our account? I'm not sure where to start with this correction.