My GF and I just returned from a 7* trip to LV. The flight and room was comped, along with a $500 folio that could be used to charge food, etc. We charged the Pitbull tix, along with several meals, which totaled $789, so there was $289 in excess room charges. I was given the option of paying that using my reward credits or my credit card. I voted for neither and asked to speak to a host on duty. I politely asked the host if she could give me a discretionary comp. She hemmed and hawed and said that they do not offer discretionary comps if the customer has a reward credit balance; they can only take it out of the RC first, and if there's none left, then they can consider a discretionary comp. This was something that I already knew but figured it wouldn't hurt to give it a try, and was almost resigned to give in and say "ok, whatever". But the host then asked if my GF had her own Total Rewards account. I said yes, but explained that she's only a Gold tier, with about 3,120 in tier credits and about $12 worth of reward credits. The host said "Perfect", that's exactly what she was looking for. I was puzzled until the host explained that she could apply $199 of the $289 excess to my GF's TR account, use up the 1200 in RC and deduct the rest ($187) as a discretionary comp since my GF has no more reward credits. This way, I would only have to use about 9000 of my own reward credits for the remaining balance (289-199=90). This was not something that I had thought of and wanted to pass this along those who travel together and have their own individual TR accounts and one account has significantly less RC than the other.