You can curve a wall using the Curve tool. Once the tool is active, you can click and drag the wall to curve it, or select a point to curve to.
To curve a wall by clicking and dragging:
Click the wall to select it.
Right-click and select Curve, or select Edit > Modify Elements > Curve.
Click and drag the wall to the desired curve.
Release your mouse button.
To curve a wall to a selected point:
Click the wall to select it.
Right-click in and select Curve, or select Edit > Modify Elements > Curve.
Select the point you want to curve to. The wall automatically curves to the point.
Click to finish.