Cancel passport appointment, can I schedule later or loose appointment

[Unregistered]

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.