you can cancel any number of passengers from an e-ticket without cancelling the entire ticket...
When you will click the option cancel e-ticket, the window will appear re-enter your password..
After entering password the next window will show tickets booked by you..
Out of that select the ticket you wish to cancel and click cancel ticket..
After...
more... that next window will appear consisting list of passengers in the ticket.. Select the passengers you want to cancel by clicking in the box appearing in front of them.. You will be asked to confirm the cancellation...