Briefing a bit more rule and regulations of Indian railways below:

Intermediate Stations Pertaining Reservations

The intermediate stations those who are not having computerized reservation facility; their requisition for berth reservation for all classes is only initiated when journey tickets are purchased. The station master of the intermediate station should be informed seventy two hours before the schedule time of the train to be departed. So, that as soon as possible the request could be send to the stations having computerized reservation facility.

Due to passengers arriving late Cancellation of Reservation

The passenger, whose seat or berth is reserved in advance, does not turn up to the station ten minutes before the departure of the train, strict action is highlighted and the seat is provided to the passenger of waiting or RAC list, whom so ever is on the priority.

Boarding Point to be Changed, In such a case:

1) A passenger should submit a request in writing, 24 hours before the departure time.
2) Such accommodation can also be adjusted by the railway administration.
3) Refund is not permissible for the portion, the passenger has not traveled.