How to refund/return the remaing of AP Prepayment invoice

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Ex: I created a Prepayment invoice for (Employee) or suppliers and the invoice Amount is 1000 USD.

And apply it on standard invoice with amount 800 USD and the remaining amount of Prepayment is 200 USD.

My question: I need to refund or return the remaining amount 200 USD to supplier to close this prepayment and need the more solutions.

Thanks