Cancel passport appointment, can I schedule later or loose appointment

Actually I had my first appointment on 22nd March but since my documents were not ready yet I rescheduled it to 1st April but again unfortunately my documents are not ready yet. I only have 1 chance to reschedule and I am getting a date close to 7th April but I have company trip.
There is one more option to "Cancel the appointment" but I think that if I click it then I wont be able to reschedule again.

I suggest you to visit PSK on this appointment and ask them to give you desired date. Other way is to not to cancel and do nothing and book appointment after few days, then you will get new dates.