To credit an Exchange unit select the Credit Exchange Unit option on the E.P.O.S window.
The following window will then appear on window:
Enter the required part number and the invoice number that you are crediting the surcharge from. Select Search.
This will then create a credit for the Surcharge as shown below:
Click the Customer option on the left hand side of the window.
This will automatically display the required customer on window. Select Confirm to raise the credit note.