KLM Royal Dutch Airlines’ cancellation policy varies depending on the ticket type, fare rules and booking conditions. Passengers generally have the option to cancel eligible tickets within 24 hours of booking and receive a full refund. Cancellation fees may apply after this period and refunds vary depending on fare type and expiration date. Flexibility may be available due to unforeseen circumstances such as flight changes or travel restrictions. Passengers can cancel their reservations online through the KLM website or mobile app or contact customer service.