Post in alot of forums that DON'T SAY "post count don't count" and you'll change it from the kanto badges to the Johto and so on Until the Battle Frontier symbols. BUT DON'T SPAM IN THEM, I mean don't say: Hi! just to increse you're "Rank". BUT they don't mean anything, it's just for fun! And to know how much people post in threads that count for the Post count.
IF you're talking about changing the LETTERS in them, go to User CP and click on Edit profile the first thing you'll see is "costum user title" and write anything you want![don't speak badly or just write 2 letters in it!]
For example, mine's "Deoxys Seeker" Hope it helped!
EDIT: If you have any more questions, Pm me! I'll answer all I can!