If your flight is delayed or cancelled you, of course, want to know as soon as possible what to expect. In some instances KLM will contact you directly. If this is impossible, because staff are too busy in the event of a major disruption, these are the quickest ways to find out what the situation is and how it affects your travel plans.

http://blog.klm.com/how-to-reach-klm-if-my-flight-is-cancelled/