so, this subject has come up before and I remember being surprised by the answer. I believe that if you marry a NEW ap to the car, it will overwrite the old one. Then when you unmarry it, it will flash back to stock.
Conventional wisdom says that you need the exact AP to do this, but I remember seeing somewhere that you do not. I'll try and find the post....
for example:
http://forums.nasioc.com/forums/showthread.php?t=2100396