My wife is currently working on H1b. She is going to start with a Phd program and has received her COS (I-797), F1 approval which is valid from July 30th, 2010 to the end date of the program.

Her H1b visa stamp on the passport does not expire until 31st May 2011 and she will be employed with her current company till the end of July.

Due to some family emergency she will have to travel to India next week, but she will be returning back a week before July 30th. Does she need to get the F1 stamped while she is India to travel back into the country? Or will she be able to travel back with her existing visa?