You can curve a path segment using the Curve tool. Once the tool is active, you can click and drag the path to curve it, or select a point to curve to.
To curve a path by clicking and dragging:
Click on the path to select it. If the path has multiple segments, make sure you click on the specific segment you want to curve.
Right-click and select Curve, or select Edit > Modify Elements > Curve.
Click and drag the path to the desired curve.
Release your mouse button.
To curve a path to a selected point:
Click on the path to select it. If the path has multiple segments, make sure you click on the specific segment you want to curve.
Right-click and select Curve, or select Edit > Modify Elements > Curve.
Select the point you want to curve to. The path automatically curves to the point.
Click to finish.