Sometiumes I get lucky by calling the hotel itself and asking for "inhouse reservations". When I worked for Hilton we turned off CRS (central reservations system) when we were sold out so that we wouldn't oversell (Hilton computer system's automotically oversell by about 2%). Because we very rarely turned CRS back on for that day when we got cancelations we would only give the rooms to those who called inhouse reservations or walked in. As for alotted rooms on Expedia, Orbitz, etc., Hilton dosn't do that anymore. Those companies have access to the reservations system and make their own reservations based on avalibility.