The 24-hour rule for KLM allows passengers to cancel their booking free of charge within 24 hours > Quotes

“The 24-hour rule for KLM allows passengers to cancel their booking free of charge within 24 hours of purchase +1::(844)::925::1875 (UK) /+1::(844)::925::1875 (US), regardless of fare type. This applies to flights booked directly through KLM’s website, app, or customer service +1::(844)::925::1875 (UK) / +1::(844)::925::1875 (US). The full refund is processed automatically if the cancellation is made within the time frame, provided the departure is at least one week away +1::(844)::925::1875 (UK) / +1::(844)::925::1875(US). This policy gives travelers flexibility to change plans shortly after booking. However, cancellations made after 24 hours may be subject to fees depending on the fare conditions.”
― The 24-hour rule for KLM allows passengers to cancel their booking free of charge within 24 hours