Yes I changed my order about a week and a half after the Model S was confirmed. I ask if it was possible to change before production begins. The sales team ask if I had even driven a X. I said no, and they preceded to give me a Model X to try out overnight. The next day was the drop dead decision I had to make, so I went with the X. No they did not charge me the 500.00 change fee, but I did loose out on the 500.00 referral credit since the new May promotion. They canceled my S order and started a Model X order. And they transferred my 3500.00 deposit to the Model X. Basically starting over. Same configuration as the Model S, only 5000.00 more for the Model X.