Change employer after H1B without CoS

I work with Employer A and Employer B applied for my H1B this March 2014.

Current status is that I129 PETITION FOR A NONIMMIGRANT WORKER is approved.

My application was submitted WITHOUT Change of Status so I have to go outside of US to get stamped before I start working for Employer B.

At this point can I change job to new Employer C?

Is it possible to transfer my H1B to a new Employer C when I have not started working with Employer B?

I do not have any forms like I129 or 1797 with me. All I have is the receipt number with USCIS with which I check status.

@Saurabh and team
Request you to please answer the question above.