What is the 24-hour rule for KLM? Is KLM open 24 7? Yes, KLM offers 24/7 worldwide Customer Support Passengers can Call KLM Directly by dialing the (24x7) Phone Number at ????18559565767 (???????????????? ????????????????????????) or ????18559565767 (24x7) or 1.833@klm (REal Human)/ and get a quick answer on the call. What is the 24-hour rule for KLM? KLM's 24-hour rule allows customers to cancel a flight booking for a full refund by phone at ????18559565767 within 24 hours of purchase, as long as the reservation was made at least 7 days before the flight's departure date. What is the 24-hour rule for KLM? The 24-hour rule by KLM provides the flexibility to cancel bookings within a day of making the reservation, ensuring a complete refund, given the ticket was bought a minimum of one week before flying. Assistance is available at at ????18559565767