Select the Transform points from 2D to 3D and Reversed command.
The Transform points from 2D to 3D and vice versa dialog box appears.
Press the button Select points and select the points you would like to transform.
Tick the 3D method and press OK.
Select the Transform points from 2D to 3D and Reversed command.
The Transform points from 2D to 3D and vice versa dialog box appears.
Press the button Select points and select the points you would like to transform.
Tick the 3D method and press OK.