can't make or receive calls after iOS 6 update

I had this happen this morning. I fixed mine by restarting the phone. Hold the power button and the home button until it reboots to the apple screen, let go of power button but hold home button for another 10 sec on apple screen, wait for the restart, then your phone should say "waiting to activate..." Or something like that. After a minute or two you should be golden

Another thing to try, go to settings-->general-->cellular-->en turn cellular data off then back on and see if that works

On the phone screen just dial ##87383# Then press Call.

This will update the phone and allows calls to come in and out again.

Taks about two minutes to do the update.

Sorry. I am told the code may only work on Sprint.

Yes, Arcade4, it is a Sprint fix. I went into the Sprint store and he said it was a Sprint issue and that the update for Sprint iphone that is out now had one small piece missing that caused some of their iphones not to be able to send and receive calls. It must be a pretty big problem because they had him stationed at the door doing the fix for people. Your above method is what he said to do. It worked on mine with no problems at all.