H4 to H1 COS, H1 filed in counslar processing


My husband is in US on H4 Visa. He filed for H1 in consular processing and still waiting for result, it is showing as initial review as today. My questions are:

  1. If H1 gets approved, can he file a COS from h4 to H1 and once COS is done , can he start working on H1 or does he has to go back to India and get H1 stamped and then come back.

  2. if he gets an RFE on H1, can he apply for COS while replying to that RFE?

  3. Can he do a premium processing while filing COS from h4 to h1b

Please answer.

Thanks in Advance for your help.

This is Swetha, i need some information on which consultancy has filed H1 for you, iam looking for a sponsor, worked in Java for 7yrs, currently iam on H4 and willing for COS to H1, it would be great help if you can provide me that information.