At times when I go to make an award reservation on a hotel website, I do not see what I want or the site indicates there is no availability. When this happens, I do not give up. Instead I call the hotel and speak with a live person about the reservation that I want. Many times, they find rooms that I was unable to see on the site and I book award nights via the phone.
I have found this especially to be true with Starwood Resorts. The phone is how I got both of our suites on our trips to London and Costa Rica. The suites were not listed on the SPG site but with one call, I booked them!
I also find this to be true with some airlines. It seems that the phone representatives have better search tools to at times, find more award flights. In addition, they can easily change dates and airports to search if you are flexible. Just be careful that there is not a booking fee to book a flight via the phone instead of online.
So pick up the phone when you don’t see what you want. It may be worth it!