I have a reservation for two weeks at the Sheraton Vistana Resort in a 2-bedroom villa. I got a pretty good price but have since seen the offers on Skyauction and wonder whether I should try for an even lower price for the first week (the second week is not available). I'm not sure if the hotel would let me change my existing reservation to scale back to the second week, so that I would have one week at the Skyauction price, then one week at the original price. Do you think it's worth the risk? I don't want to end up without a place to stay -- and our second week is over July 4, so accommodations are scarce. The minimum bid price last night was $411 for a week -- anyone know what a two-bedroom usually goes for, for a 7-day stay?