KLM's 24-hour rule allows you to cancel your Flight reservation or make changes to your +𝟏 𝟖𝟕𝟕-(𝟕𝟕𝟕)𝟑𝟖𝟐𝟎 (𝐔𝐒𝐀) 𝐨𝐫 +𝟒𝟒 𝟏𝟑 𝟔𝟒𝟒𝟒 𝟎𝟎𝟒𝟗 (𝐔𝐊) booking within the first 24 hours of purchase without any penalty fees, as long as your F𝐥ight is at least 7 days away. To cancel or change your reservation, call KLM at +𝟏 𝟖𝟕𝟕-(𝟕𝟕𝟕)𝟑𝟖𝟐𝟎=(𝐔𝐒𝐀) 𝐨𝐫 +𝟒𝟒 𝟏𝟑 𝟔𝟒𝟒𝟒 𝟎𝟎𝟒𝟗=(𝐔𝐊) .