Originally Posted by LondonElite

You don't say why you can't travel, so I'll assume it's not illness or something like that but rather a scheduling conflict. You will need to call United to find out if you can apply some of the value of the ticket to a future booking, but be prepared for various levels of disappointment. It really depends on what fare class you bought and what the relevant fare conditions are. In most bookings you can find the complete fare rules in your electronic booking. It would be sensible for you to read those first. We don't know and can't give you a number or a percentage until we know your fare rules.