1) Might be some other priorities planned on that same day and for which you can't attend to PSK
2) You might forget the date and miss online passport appointment date or may be at last minute
Don't Miss How to apply passport online in India
But in case you are aware that you can't visit PSK for your passport appointment date then you can reschedule or cancel your appointment. In such a case you have to make sure that you reschedule/cancel your appointment at least 15 hours before the scheduled date/time. To do the same you can follow the below steps as per the passport portal guideline.
Steps to Cancel/Reschedule Pasport Appointment
1. Go to Saved/Submitted Applications screen and click on Schedule Appointment link.
2. Click the Reschedule Appointment/Cancel Appointment button. Then you will get a confirmation message.
3. If you are rescheduling appointment then you might changes the PSK location and then confirm your selection.
4. Then select the available slot for next appointment like you did last time and proceed further.
Don't Miss How to get passport appointment quickly