Using AP if H1b stamping fails

[jminu]

Hi experts,
I have a H1 and an EAD/AP via my husband's GC application. I plan to go for stamping in Dec in Chennai.

If the H1b stamping is not successful I want to know the process to come back on AP

Can I just re-enter on AP? Should my employer submit COS with USCIS

Pls help me understand the process

Thanks,
Mina