Changing from staccato to legato etc.

My MIDI or VST track is connected to a cello VSTi, and for some reason, some notes are played back as staccato, even though they are really long and have the same velocity, volume, modulation and so on. The sample is a staccato one, while the legato-sounding notes are legato samples. But rather than going through every single note manually and changing the samples assigned to them, is there any easier way to change from staccato to legato for example?

Thanks in advance!