Understandably, such a major change to a character is subject to a lengthy list of eligibility requirements, limitations, and consequences. There are a handful of main classes that cannot take part in the event, and certain sub and main class combinations won't work either. Subclass certified skills are reset, and certificates are removed. Above all, this process can only occur once, so you'll need to be sure of your decision. Check out the full details at the "Choose your Destiny" page -- we're expecting more date and time details to be given some time soon.