For cancellation of tickets purchased from a computerized reservation centre please visit any computerized reservation centre and fill in a form for cancellation giving information like the train name and number, name(s) of passenger(s), date of travel etc. and present it to the booking clerk for cancellation.
For cancellation of E-tickets purchased from IRCTC:
E-Tickets (Reservations) can be cancelled only through Internet till Chart preparation of the train and it is not allowed at face to face Railway Counters. If you wish to cancel his e-Ticket, you can do so till the time...
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of chart preparation for the train (which is normally 4 hours before the scheduled departure of the train from the train starting station) through the Internet. You can log on to www.irctc.co.in and go to Booked Tickets link and select the ticket to be cancelled and can initiate the cancellation by selecting the passengers to be cancelled. Cancellation would b e confirmed online and the refund would be credited back to the account used for booking as for normal Internet tickets. If there is any partial cancellation of ticket please ensure that the modified ticket (Electronic Reservation Slip) is printed separately as for the original ticket.
For any claims on e-tickets to be cancelled after the preparation of Reservation charts, you have to send an email at the earliest possible time to etickets@irctc.co.in giving full details of the ticket and stating the claim, which would then be processed by IRCTC with the Railway administration offline and refunds as sanctioned by the Railway administration would be credited back to your account.