I currently hold a ticket from EWR-CDG-BUD, and then returning BUD-CDG-EWR. The ticket was purchased with Calrson Wagonlit, and the EWR-CDG-EWR segments are on CO metal, but the CDG-BUD-CDG segments are on on Malev metal.

Can I stay in Paris, and skip the CDG-BUD-CDG segments, without my CO flight back to EWR being cancelled? In other words, even though all 4 segments are showing on co.com, do the two computer systems "talk" to each other in real time? Will Malev contact CO and say, "Hey, he never showed up for his flight to Budapest, so cancel him for his flight back to EWR!"