I am staying with family at the Tokyo Bay Hilton @ Disneyland next week. It's a 3-day cancel reservation so I'm within the change window. It is a points and money combo booking. I need to shorten the stay by one day. However, when I try to do this online, the system won't let me because my room category is sold out. When I call the Honors line, the agents seem to be struggling with how to help me do this without risking losing the room. The last guy told me he would cancel and re-book, but I am concerned during that process someone else will take the last room in that category. I really need to be able to talk to someone who's not just sitting at a computer doing the same thing I can on Hilton.com, but can somehow hold that room inventory while they modify the reservation.

Any advice on this?

Thanks!