I have a customer that has ordered a product that isn't ready to ship. To compensate the customer, I'd like to offer a discount by applying a coupon code on their pending order.
I'm aware that I can cancel the order and then apply the discount, but since this is a credit card transaction, I do not want to cancel the order or obligate the customer to "checkout" for a second time.
How can a discount be applied to an existing order ? (without cancelling)