I booked a room with a free night and then emailed someone in the "Executive Office Administration" at the specific hotel about paying for a room upgrade. We agreed to a cash price to upgrade to a suite, but he told me that he modified my reservation in the hotel's internal system and that it won't show up online or by calling HGP and nor can he email me an updated confirmation. Even when I called the front desk at the hotel, they think I'm in a standard room.
Sounds like I shouldn't trust this guy. (No, I haven't paid the cash yet.)