Worst experience ever, don't book online!
I tried to reverse a reservation because I found out later I was eligible for a different rate. I called reservations, got transferred about 3 times and the last person said she cancelled my first reservation and made a new one at the lower rate. Much to my surprise I received 2 reservation confirmations by email which made me suspicious about what she had done. I called again, was transferred and transferred, finally spoke with the local manager at the Sheraton in Sunnyvale. He said he would credit me back the increase in rate. But guess what, when I checked my credit card statement there was no credit from the Sheraton. Called the Sheraton again, 6 transfers and an hour later I found out that I now had 3 reservations and probably will be charged for all 3. Thank you Sheraton,but never again.