Status if H1B approved but COS is denied

Hello,
What is the visa status of a person if his H1B petition approves but COS (F1 to H1) is denied ?
Does he continue on F1( F1 remains valid ) till the individual goes out of country to get visa stamped or is his SEVIS terminated the moment H1B approves ?

I applied for H1B (currently on F1) and got an RFE , replied to the RFE September 23rd /today (premium processing) so expecting a response in 15 days .
Currently on F1 status with an I20 validity till October 8th 2015 , so wondering if my H1 approves by then but COS is denied what to do …

Any help please

Thanks
Nishant

Your status would remain F1 in this case.

your status will be as per your last I-94.

But my I20 expires on October 8th .
So was wondering if my H1B approves (but COS denied) after that date what will be my status ?
Will I be out of status or since my H1 has approved I can stay a couple weeks and go out to get stamping ?

Very confused

Please let me know

Thanks
Nishant