Editing orders to add one-time discounts

[Daniel_M_JHS]

We have a discount code that is available for 15% off a customer's next order when they sign up for the mailing list. My question is this: let's say a customer signs up and gets the discount code, and submits a new order but forgets to apply the discount at checkout. I know that I have the ability to edit their order and refund them 15% of their purchase, but if I do that, will the discount code be "used up" or will they still be able to create another order and use the code? Is there a setting on their customer profile that can be changed to prevent them from using the code in the future?

[StephensWorld · Accepted solution]

If you manually refund them 15% of the order, then they would be able to use the discount code on their next order. 

Whether you can disable the order or not, depends on how you're creating the discount code. If it's the same code for all customers (with a limit of 1 use per customer), then you wouldn't be able to disable it for a specific customer. If you're using an app that generates a unique discount code for the customer when they signup, then you could disable just that specific discount code (so that they can't use it).