Confirm whether your fare allows for changes. Certain fares for KLM bookings do not allow flight changes. For example, the lowest fare option generally does not permit changes. Other fare options offer the flexibility to allow amendments with or without fees.
Click on to "Manage my Booking" link on the KLM website. You can change your reservation on the KLM website if the fare you purchased allows for changes to flights.
Select an alternate flight. Once you are logged on to the "Manage my Booking" page, you can view available alternative flights. This list will also include any applicable fees or costs associated with the new flight.
Pay the change fee. Certain fares require payment of a fee for new flights before your booking is reconfirmed. If the change being requested requires a fee, you must pay the fee online using a credit card.
Print the new reservation for your records. An email confirmation with the new travel details will also be sent to you.