The 24-hour rule for KLM allows passengers to cancel or modify their flight within 24 hours of booking without penalty. For assistance, contact KLM customer service at +𝟖𝟖𝟖*𝟱𝟱𝟰*𝕆𝕆𝟟𝟝 (𝚄𝚂) 𝚘𝚛 +44*𝟚𝕆*8124*𝐎666 (𝚄𝙺)t. KLM customer service is available to help with any changes to your booking within the 24-hour window.