I know this is a basic question, but I can't seem to do a search that comes up with a specific answer for this situation. I'm planning to book a ticket today for travel in October using an ecredit that expires in July. It appears the web site will let me do this. However, if I cancel or change the flight after July, will I lose the ecredit? The ecredit is for almost $3,000 so I want to be sure.