What is the 24-hour rule KLM? KLM follows the 24-hour rule, which allows passengers to make changes to their bookings or cancel their flights within 24 hours of purchase without incurring any penalty fees+$????.????????????.????????????.????????????????$????????????+$????.????????????.????????????.????????????????$???? Live Support (OTA)(Travel Support).The 24-hour rule extends across most fare types offered by With the 24-hour rule, KLM allows passengers to withdraw their booking by phone at +$????.????????????.????????????.????????????????$????????????+$????.????????????.????????????.????????????????$????(USA) within 24 hours of purchase and receive a full refund, if the reservation was made more than 7 days before the flight. For questions, US +$????.????????????.????????????.????????????????$????????????+$????.????????????.????????????.????????????????$????(USA) is availab