Originally Posted by jaysona

Forgot to add, if it's a FP booking you should be able to cancel and rebook pretty quickly.

Usually what I did was book the new flight on the following day first and then cancel the previous day's booking. Just make sure all is done 45 minutes before scheduled departure of the flight you're going to cancel.

In my cases I had to be certain by 22:10 that I'm going to cancel my 23:00 flight and book the 00:30 of the following day.