There is a facility by which we can modify a ticket. This facility is only available at Reservation counters at stations.I have made use of it but don't know the exact rules and charges for it. Suppose I have a confirmed ticket for say 15 Mar but I cannot travel on that date but on another date say 20 Mar, then I can modify the ticket for the new date in same train same class by paying some charges which would be cheaper as compared to canceling the ticket and booking a fresh one. I had done a modification in a ticket in sleeper class by paying Rs 20.