Qualified for B2 Visa waiver and drop box question

My father qualifies for B2 Visa waiver (since he already had B2 Visa in past and visited USA in past).
I applied for new B2 Visa but dropbox (VAC) appointment in Mumbai has first availability in October 2022.
Is there any way to have Visa earlier?
If I take appointment for October 2022, can I change it to earlier date if there is any availability?


Only way is to keep looking for earlier appointment.

Yes you can cancel the existing and book a new one.

there is a limit on how many time you can reschedule. Post that you have pay the fees again.