Withdraw H1B petition filed by new employer to continue with Old employer?

[communicator]

I am trying to change my employer. New employer got a job for me and filed H1B petition with New client name in the petition supporting documents. But the client which he mentioned in the documents sent to USCIS is delaying the joining date. Not sure whether that client want me to get to the location to join the project. So, in this situation if a get an RFE from USCIS asking for the client letters I don't think I can provide them if new client doesn't let me to join. Can I withdraw the petition at this point and continue with the old employer who is holding my current H1B?