Reverting H4 back to H1

I worked on H-1 for a couple of years and then converted to H4 a few months ago and my previous employer has withdrawn my petition.

I am looking to join a new employer and again get on H-1 but I have some questions-

  1. When I find a new employer, will he have to file for a transfer of my H-1 or a new H-1B petition for me? (since previous is withdrawn)?

  2. Since the premium processing is not working currently, when can I start working for the new employer? I was told by many that I just need to get the receipt number and not the actual approval to start working. (There are not any employers who will wait for months to get approval).

I am not sure about transferring an withdrawn petition.

But in case allowed, you will have to apply for a transfer and a change of status(H4 to H1).

Unless your COS is approved, you cant work.

In your case its not a simple transfer to work with a receipt number. You have to apply for COS(H4 to H1).