you should turn in your H1b I-94 when you depart

and you will be issued a new one when you come back with AP, your new I-94 would bear a stamp that says paroled until a date, which is about a yr from the date your reenter the US border.My lawyer said I can just ignore the date, and not worry about my status.

And you can extend your H visa if you do not change employer. I just did the whole thing beginning this yr. Hope you find this information helpful.