OK, I have a 1st gen WIFI iPad (no 3G/4G). I ordered AT&T iPad which was just delivered and I picked up a VZW iPad at Apple store this morning. I'd like to interchange them to see if they work but I just don't know how (if you can) to remove the sim card. I see a little whole on the top that I can fit a paper clip head into but it's not opening. Any help out there? Thanks.