Hi Bond, You can go on OPT and re-enter US if you are working full-time for your current employer.. of course you need to get a letter from your employer before you leave... but in this case since your friend's visa has already expired it is possible that the US Embassy may not stamp them the F1 visa again... because they already finished their studies.... so I would suggest not to take risk by going now.... HI Bhadgaule, in your case,I think you need to do all the procedure again.... just like what you did when you applied for the student visa first