Rotating wall.

[jfjacques]

This is a parapet. 

I would like to rotate/taper it ? so that it's it is vertical but it's top is angled to become flush with the other parapets.

Is this possible? 

[ToanDN]

Create an in place model, void sweep, pick 3d edge and pick an edge of the
parapet wall, draw the triangle profile matching the slope of the adjacent
parapet, lock it, finish the void sweep, cut geometry the parapet wall with
the void, finish the in place model.