I hate to cancel the plane tickets.
Booking online is damn easy, but once you are done that you are under the evil shadow. I won't suggest buying the air tickets if you are not sure of your travel plans. Rescheduling is expensive enough and they don't encourage the cancellations at all. They charge heavily if you try to cancel the tickets. I have come to the conclusion that all these airlines make more money with cancellations than the actual sale of tickets.
I had to pay about 1/3rd of the ticket price as the cancellation charges. I was so depressed with the whole thing, that I was about to book a wrong ticket.
Ouch! Good that I realized it in time.