Select & Move One Part While Viewing Multiple Parts i Key Editor

SOLVED: I worked it out. I needed to select ‘All part on active track’ in the Part Editing Mode Drop-down, and then make the track I needed to change the 'active track and then go to edit>select>all.

I’m very new to Cubase, so apologies for my clunky jargon.

In Cubase Pro 14, I would like to view more than one midi part in the key editor, and then select only one part (or section of a part) and move that in relation to the other parts.

For example, as in the screenshot, while viewing the Cello (blue) and Viola (pink) parts, I need to move the violas along a bar.

Can this be done, and if so, can you walk me through it please?