separating R and L tracks from stereo import

I am a new user of Cubase LE6.0.5

I have imported a stereo wav file and I need to edit the Left channel. In audacity I simply select “split stereo” and the two channels are separated for processing (and later rejoining). I cannot find this option in cubase LE. I have seen some questions about this on the forum but no answers.

Any help appreciated