Presently I am staying on H4 VISA,this year I am planning to do H1B ,my H4 expires date on July 31 st, 2015 .If i will get the H1 B that effect from OCT 1 right?in this case can i apply for H4 extension. my friends suggest me if i will go for H4 extension H1 going to be canceled.so what can i do here.(my question is can possiblity to stay here August 1 st to september 31 st)
Surprised at the advise of your friends. If your H4 is expired then you have to apply for extension to stay in USA. It does not affect your H1 in any fashion. Your H4 will be extended on current I94 and you will not get a new I94. But if you go out of country then it impacts your H1, you need to apply for an amendment on your H1 with your new I-94. If you don’t apply for H4 extension thinking that you will get H1, then your stay between July and Oct is illegal, you will get into legal complications later.