We have an upcoming stay at the the Hyatt Tsim Sha Tsui in Hong Kong, and I called last week to apply a suite upgrade to our reservation. I was told that most of the hotel was sold out for the first half of our stay (and I checked online to confirm), so the agent applied the upgrade to the second half. Yesterday I decided to check availability again, and the website showed the regency suite as being available for all 4 nights of our stay (as well as many other room types). I called and was able to get the upgrade applied to our entire stay. Cool. I'm just wondering if this is a pretty common occurrence and what the cause is? A hotel being sold out for a particular time frame, and then suddenly having lots of availability. Did a tour group suddenly cancel? Were rooms set aside for third party booking agency and then released back to the hotel?