Need an advice on my H1B situation

I got laid off and got a new job. Company A filed for my transfer on 60th day in the grace period. They filed in regular processing on August 27th.

Got an offer from Company B and they are willing to Transfer in Premium Processing.

So I upgraded my current company A petition to premium processing and it got an RFE. However, I am still waiting for the notice from USCIS. Now, as I am on RFE, can I resign from the job with company A and join company B? What are the consequences? I do not want to stay with Company A anymore and would like to know what are the possible options? Since Especially current company A petition might take one more month for approval, although Company B would be willing to wait, I do not want to continue in Company A!!