Ok, we had an online customer overpay his order using a money order. So, when I tendered the money order, he had about $45 coming back to him. Well, he just wanted that applied to his account. So, I selected (Payment) and applied the $45 to his account. It warned me that it was an overpayment and I clicked OK.
Now, on his next sale, how do I apply that $45 credit?