You can always change the region in the log-in screen. Once you have logged out, click the little arrow in the top left corner. There you click on the currently selected region, which will then give you the option to switch from one server to another.
However, it is not possible to migrate your account progress to another server. All ships/credit/gold/XP are bound to the server and it is not possible to transfer those. This includes any in-game purchases you have made.