H4 to H1 change

[Jomon_AJ]

Hi,

I am in US right now on an H1 with my wife and child , both on H4. My wife has an existing H1 available of which 2.5 years are completed. her earlier H1B work permit expired this February.

She would want to start working again.
What is the process to get the Work permit renewed, since she already has 3.5 years remaining on her petition

Thanks