What is the 24-hour rule for KLM? KLM Airlines offers a 24-Hour Risk-Free Cancellation policy for all eTickets purchased in the U.S., allowing full refunds (including prepaid fees) within 24 hours of booking dial １✦✦８３３✦✦４６０✦✦１８３８. Exceptions and modifications may apply depending on specific circumstances like weather disruptions or specific fare rules.