tomer

Hi, I have a client that has placed an order for several domains. I would like to give this client a % discount from the full order price. Can anyone suggest how to do this? I know I can use promotional codes, but that means I have to cancel the current order and place a new order with the promotional code. How can I add a discount to an existing order, so that the invoice will be updated and say - 20% discount for example? I would appreciate your help.