To refund an order in back office, find the order in Sales History or scan the barcode on the sale screen.

Within the order, tap Refund or Exchange.

It will now take you back to the sales screen and the order details will be brought up.

Tap next to the products that are to be refunded or exchanged, then tap Refund or Exchange. If a customer is wanting to exchange an item, add that item to the order and the difference owed will be automatically added to the order.

The payment screen will then appear, letting you know how much is to be refunded.