L2 to H1. H1 petition is in review for 5 months.

My wife is on L2 and her visa/EAD/i-94 is valid till oct 28,2012.

My employer had filled H1(premium) for me and it is approved and will be applicable from oct 1 but H1(regular) for my wife is still in initial review stage. H1 was applied in first half of april.

Can she stay in US after sept 30 as i will move to h1 from oct 1.

also if we start her H4 now and in between her H1 gets approve, which visa will be valid?