Change of status from B1 to H1B

[skorah]

Hi,
I have entered US on my B1 visa(Employer A) and will expire in another 10 days.
I have a H1B approved(I-797B) sponsored by employer B and have found a job.
Employer B is willing to apply for a change of status from B1 to H1.

I need your help to understand if i can stay beyond 10 days until decision of my COS application is received.

Thanks