https://tabellaesupport.microsoftcrmportals.com/forums/general-discussion/07f9900a-3dc9-ef11-a81b-0022489f0209 (Modify/Cancel) +[[+1-844-643-3377]] What is the KLM 24 hour rule? The "KLM 24-hour rule" allows passengers to make changes or cancellations [[+1-844-643-3377]]; to their flight bookings within 24 hours of purchasing, without incurring extra fees [[+1-844-643-3377]];.