Your UDID is build into your device. There is absolutely no way of changing it with any app what's so ever. There is an app on cydia that spoofs your UDID, but it isn't changing it. Your device ID will never change, even if you restore your iOS device. As I said, it's build into the code. That's why the developers of iPhone graal took the advantage of UDID. When you connect to graal, your app connects with graal's database and matches your UDID with the one in the database to find your PC ID. When it finds your ID, graal loads the profile, items, etc. During an account transfer, the only thing that happens is that the PC IDs switch devices. Nothing else happens. Like I said, UDIDs are configured in the device's hardware and are impossible to change.