Cutting off a wall

[tomek_111]

I've got a problem. I have already done a wall and finished it (a four-storey wall). But it's too high and I'd like to cut off the highiest storey from my wall. How to do it without making a new one?

[Highrise99]

Hope this helps:
Step 1
Select the wall.  Go into the modifier tab and click on the lightbulb next to extrude (assuming that the wall is an extrude) so that it turns from white to gray.  It is temporarily disabled, don't worry, you can turn it back on later.
Step 2
Select mesh edditing from the modifier stack.  At the top of the mesh edditing modifier, select face if you have window(s) on the top floor.  If not move on to the next step.  Select the window(s) you want to get rid of and press delete.
Step 3
Now select vertex.  select the top two vetecies and move them down to the top of the third level.
Step 4
Click the lightbulb again to turn extrude back on again.