Fares often change based on other customers making new bookings or changing their plans. Some flights or dates can be more popular than others, and therefore could be more expensive. This can mean that the fare that applies to your new itinerary is more expensive than the fare you’ve paid.
If this is the case, you would need to pay this difference in fare – in addition to any change fees – to amend your booking. Any additional costs to amend your booking will be displayed and can be paid when you make a change online.
Please note these costs are only guaranteed when you have successfully completed the change.