Just called GP Customer Service to request Diamond Suite upgrades for two reservations. For both I was told there were no suites available. Question: what suite type needs to be available? (the agent didn't know) Case 1: Park Hyatt Hamburg Looking at the list of room types it appears the lowest suite type is "Park Suite King/Queen/Twin". For my dates, hyatt.com shows availability at the Hyatt Daily Rate (EUR 300 more than the lowest priced room at EUR 285). Is this a case of them being willing to sell a higher-level suite for the lower-level price but not offer it for upgrades? (I'll try another agent later today) Case 2: GH Seoul hyatt.com shows availability for Grand Executive Suite, which appears to be one level above Grand Suite (not for sale). I take it they only upgrade to the lowest level? This is my 2nd year as Diamond, and it looks like I'll end up with 4 unused upgrade certs. What is your success rate?