Ok. So it is indeed not there.
I hope Apple takes the suggestion and adds it. Seems logical and relatively simple. I've run into the issue several times. Face time is great but not always needed for an entire call (Say you want to show somebody something or they call you up to look for something in the house when they are away, bandwidth stinks, etc....) And if you hang up, the phone keeps dialing you back-- in Face time.
I'm surprised this is already not a feature.
This is my first time on the support forum but if someone can upvote it, if that is an option, then I would appreciate it.