You can issue a refund using the "Issue Refund" function in the control panel.
Note: You may be required to enter a manager override password.
On the Issue Refund screen, you'll see the following options
Type: Payment method of the transaction being refunded. Cash, Credit, Check, and Gift Card are the options.
Tax Rate 1(2,3): Tax rate for the refund
Reason: The reason for the reason.
Amount: This is where you enter the amount of the refund.
Issue Refund: This will process the refund
Close: This will return you to the control panel.