I had booked CDG Sheraton a few years ago on SPG50 rate using my SPG points. But I wasn't able to go so I transferred the reservation to a colleague. He paid with his AMEX. Hotel treated him as if he were me and I got credit for the stay.
This was all up and up, so the hotel did me a favor by giving me credit. Reverse situation from yours. YMMV.
Last edited by CIT85; Mar 27, 2016 at 7:05 pm
Reason: Reread OP description. Reverse situation.