H1B Strange Question!!!

[ice9]

Hi All, Its a very odd situation I am facing right now. Any help would be highly appreciated.
I have total of 2 approved H1B's one through CompanyA and the other through CompanyB
I am working for CompanyA right now
I have a scheduled appointment in India for getting H1b stamping through CompanyA's I-129 (made online reservation with H1b petetion # of CompanyA)

Q> Can I get H1b stamped through CompanyB in India?
Q> Can I still use the scheduled appointment date ?

Please help~!!!!!

Thanks a lot