KLM follows the 24-hour rule, which allows passengers to make changes to their bookings or cancel their Flights within 24 hours of purchase KLM's 24-hour rule allows for free changes or cancellations within 24 hours of booking. You can talk/chat/speak with a customer service agent
https://community.jungleworks.com/t/what-is-the-cancelation-policy-for-klm/60557
