Hello Ramita6,

Typically, when someone enters the U.S., supposedly for a short visit (e.g. B-1 or B-2) and then tries to change it to a longer term visa (L-1, H-1, etc.), the INS may frown upon it (and may not grant it), but the consulates definitely frown upon it. In most of these cases is to avoid this type of change. If you have already obtained the change, it may be very difficult to procure a visa when you need to travel abroad.

I hope it will help you. Please contact me if you need more clarification.

Thanks

Prani