Actually, I'm just switching the batteries. I keep the one fob in the house as a backup. That's why I'm thinking the PATS. Because neither one will work unless I reprogram. There is no power interuption from the car either. I read on a UK site to unplug the green and blue connections on the PATS box for an hour or so, but that didn't work either. Some claimed it worked for them.
And yes, I've done both at the same time.