If the transaction is from the current business date:

Click on the order look up button. (Please note that your Order look up button may be in a different spot on the bottom function bar but it will be on the bottom function bar.)

Click on the order that you need to refund and bring it up.

Highlight the payment line and click the remove payment button.

Click exit then go to the cash section and open up the credit card manager.

You are going to look for the same last 4 of the card number that was on the receipt.

You should notice that the transaction says Reversal. (The transaction will still show on the customers credit card statement, but the transaction has been refunded and the charge will fall off in 3-5 business days)