How to handle Credit Card offer credits on LLC taxes?

I had some expensable charges on a business credit card that were expensed to the company I was contracted to.  In this case, it was a charge for Hilton Hotels.  Shortly afterward, the credit card company credited $50 to my account for using the card at a Hilton property.  How do I treat that line item? I was already reimbursed the full amount by the company and it's not income.  Any suggestions on how to account for that?