When creating your outer walls, it is sometimes neccessary to adjust them for extensions that don't go all the way up to the roof. Here's how:

1. Select the wall you want to adjust and click on "Edit Profile" in the Modify Walls ribbon.
2. In the sketch mode that will open, draw the outline of the wall you want. Use the "Trim" command to make the lines a closed circumference.

3. After exiting the sketch-mode you are left with the wall you want.
Simple. Just one thing you need to remember: DON'T USE THIS COMMAND!

Seriously. Don't.

We've been playing around with this and it turns out that Revit will get into serious trouble once you try to attach this modified wall to other walls or roofs or floors. If you need this type of geometry, just place two separate walls of the same type. It will look the same and the bevhaviour will be a lot better.

You have been warned.