Consulate Appointment - Changing from Blanket to Individual

[bdk]

Hi..
I have an appt for Dec 2 at consulate in Chennai, for blanket L1 extension stamping. But recently I got my individual petition approved. Does anybody know whether I can still go for the same appointment? Is there any facility to keep that appointment by modifying the petition # alone?

Please help urgently. I'm leaving to India in two weeks' time.

Thanks in advance !