You can add a corner (or break-point) that will allow you to put an offset in the wall. Breakpoints can be turned into corners by changing the location. To add a break-point to a wall, press the <Ctrl> key on your keyboard while you click on the wall.
Note: The previous version of Icovia required a double-click on the wall to perform this function. Double-clicking will no longer work.
Once the break-point is in place, you will notice two wall dimensions where there was previously one. Move the break-point to correct the wall lengths. Add a break-point to the adjacent wall. Then drag the corner point inward to create an inverted corner.