Handling a partial refund on an item sale
If your transactions are changeable, you can redisplay the original invoice using the Sales Register window and make whatever changes are needed and record the transaction again. (Choosing changeable or unchangeable transactions) If the items are stock, they will be returned to stock. If the customer's paid for the items being returned, a customer credit will be created. Using the Sales Register, you can either print a refund cheque or apply the credit to another open sale for this customer.
If your transactions are unchangeable, you'll need to create a new invoice and enter negative amounts for the items being returned. Again, a customer credit will be created and stock items will be returned to stock. (To accept a partial return of items)