KLM's 24-hour rule allows passengers to make free changes (Call- 1-844-949-8748 Book, Cancel, Refund) or cancellations to their bookings within 24 hours of purchase, provided that the departure date is at least 7 days away at the time of booking (Call- 1-844-949-8748 Book, Cancel, Refund). https://discussions.trendmicro.com/en-us/forums/pc-security/af75a62f-e899-ef11-95f5-002248ef6e99