You would have to lose AP to go behind the armatar you are using's requirement. Then of course you will automatically get that armatar again once you get back up.
A no armatar option? I don't think that is needed. First, you don't have to pick an armatar at first. Second, if you picked one but don't want an armatar, then I think you are out of luck (unless youwanted to spam.)
Yeah I've thought of thinking about thinking about this and was thinking about thinking of looking for a 'No Armatar' button but my thinking didn't make it to the thinking process so no thought was made. - It's not useless, not that I'd ever change my Armatar, as it was the first thing I picked and it will be the last thing I have no interruptions in between =) But I can see a lot of people deciding they like that better, I mean in an easier language for people to understand: It's like having a supreme taco, and then trading it for a standard taco because everyone else had it, save a few(you wanted to fit in better as this metaphor goes perhaps?), and then deciding after getting around the taco stand(Armourgames), you really did want that supreme taco because it was different than everyone's elses standard taco...