you got me wrong. BP may be allowed to change only once. but not necessarily at the time of booking. even at a later date. i book a ticket 60 days in advance, but its not possible for anyone to give their exact location after 60 days at that time. so BP shd b allowed to change online after booking the tkt and nt during the booking of tkt. this does nt include any clerical / operational charge. just a twitch in software...