h4 to h1 Change of status Query related

Dear Sir,

My Wife has valid H1B through Company A and now we have decided to process h4 for my wife as she can not work for a while. Once She has travelled to USA, Is it possible to apply for change of status from h4 to h1?

In that case, what is the procedure to do that and what are the documentation that are required from Company A



Once she travels to US on H-4 visa, she will be on H-4 status. In future, any employer can file a cap-exempt petition for her along w/ COS from H-4 to H-1. She can show copy of her old approved petition as proof of having make through the cap. She will not be subject to April filing and Oct start date.