When canceling an order, it would be great to be able to do a partial refund minus a restocking fee. We don't always refund the full amount when canceling an order, as it costs us processing fees, and so, it would be great if we could refund minus a restocking fee (either as a % of the order total or $ value!) You could also allow adding items to an existing order, as we could add a "restocking fee" and minus the original items.