Contact KLM or the Airline: As soon as you realise that you've missed your flight, contact KLM Missed Flight  or the airline immediately. You can usually find the airline's customer service phone number on their website or your booking confirmation. Explain your situation and provide your booking reference, ticket number, and any other relevant details. Rebooking Options: Ask the airline about your rebooking options. Depending on the fare type, ticket conditions, and availability, you may be able to reschedule your flight for a later time on the same day or for a different day.