Class Advancement Swap?

When can one do a advancement swap? Can't seem to find info on this unless I go through swtor.com and even then the links are down or not existent.

Are you asking if you can change your advancement class after you have already chosen one? If so, you are unable to. It is a set in glue once you chosen it. You can relocate your talent points but that is it.

Oh? I suppose that's something to accept. Ty for the answer.