KLM's 24-hour rule permits travelers to make changes to their bookings or cancel their flights by phone at " ("+1~~804-853-9001(USA) & +1-~804-853-9001 (UK) ) or +1~~804-853-9001(USA) & +1-~804-853-9001 (UK)# (US)" inside 24 hours of buy without causing any punishments (Charges) or expenses