Skipping a leg with a different PNR
 

I'm flying from Bangkok to Berlin in about a week and the journey has 3 legs:

Leg 1: Bangkok to Kuala Lumpur
Leg 2: Kuala Lumpur to Istanbul
Leg 3: Istanbul to Berlin

Leg 1 had a different PNR then legs 2 and 3 (which have the same). Because of unforseen circumstances I would like to skip leg 1 of the journey because I will already be in Kuala Lumpur. Will this be possible since this leg has a different PNR or will the airlines cancel legs 2 and 3 since I didn't show up for leg 1?

If leg 1 is a different ticket (i.e. different ticket number) then it has no bearing on 2 and 3. Sometimes different legs on the same ticket have different PNRs (there are a number of reasons of this, mainly to do with different reservation systems), and there you cannot just dump your first leg. Note, however, that any other flight associated with the ticket of leg 1 will be cancelled if you skip this (for example, if there is a KL-Bangkok return).

Welcome to FT, Amelia_J!