A rescheduled train is when the time the train was supposed to leave or arrive is changed to a different time. This can be either earlier or later than originally planned. So, instead of sticking to the original schedule, the train's timing gets shifted around. This might happen for various reasons, like maintenance work on the tracks, bad weather, etc. So, if you hear that a train is rescheduled, it means you might need to check the new timing so you don't miss it!
Yes, you will get a refund on canceling the ticket if the train is rescheduled for earlier hours, and in rescheduling, the train is delayed for 3 hours or more from its scheduled departure time.