Changing Employer after I-140 approval

[KarthiMano]

Hi

I am on H1B with a consulting company since 2008 and the company applied for my GC and got approval of I-140 and my PD is January 2011. I have approved I797 till September 2014.

Now I am getting a permanent opportunity with a client who may be interested in H1B transfer.
My question if my current employer accepts and continues my GC, is it ok to transfer visa to new company and just work on H1 and not apply GC with new company.

Thanks for your help

Regards
Karthik