Confusion about updating the existing reservation is a very genuine concern that could happen to anyone. But delaying with your confusion KLM change flight would impact your travel experience as well as the booking value. So, it would be better if you follow the steps as explained below in a queue.

• It would be best if you initially headed to the official homepage of KLM Airlines. 
• After that, you should hit the “My Trips” tab at the top of the screen.
• Then, you should enter your last name and booking reference into the required field.
• Tap on the Continue tab and select the reservation you initially want to update.
• Then, you should follow the on-screen instructions to change your flight. 
• Further, you must pay the applicable fee for editing a flight on KLM Airlines.
• Lastly, seek a confirmation message to your registered contact number and email inbox.