Not all Brands or Retailers support the ability to cancel codes via an API call. However that does not mean that all sales cannot be cancelled.
If, as a Retailer, you have agreed to cancel a code manually with your processor, then you will need to also manually update the order in the Reward Cloud Hub. If you don't then you're reporting and that of your Partner's will be inaccurate.
Marking a sale as cancelled is simple.
Step 1: Find the order that you have already cancelled
Step 2: Click the cancel button
Remember that this does not cancel the code, this has to be done on your end with your processor. This just marks a code as cancelled.
Step 3: Code cancelled