H1 transfer while Wife (H4) in India

I'm working on H1B visa with employerA (I797 valid until 2015) planning to change employer to employerB

My spouse got her H4 having employerA annotation on her visa (valid until 2015) is still in India. Does she need to travel to US even before I change to employerB?

If she can travel after I change to employerB do I need to file for a transfer of her visa to my new employerB once she is here?

There is no need for her to re-appear for visa stamping. Once your transfer is approved, she can travel using the current visa stamp and your new petition (in addition to other supporting documents related to your marriage and your employment w/ new company).

Thanks for the quick response…
I was worried that if I change employer they would cancel her H4 visa
So, there is no need to transfer her H4 visa to new employer once she is here in US

As part of their exit process, your employer can ask you to submit the passports for visa cancellation. The consulate will cancel it and mark it as “Canceled without Prejudice”.

If this happens, then she will have to re-appear for stamping. If this doesn’t happen, then she can travel on previous visa stamp.