In PowerPoint you rotate shapes using the green rotation handle that appears when you select a shape. However, did you ever notice that the open line shape in PowerPoint doesn’t show a green rotation handle? Even though you may think that you hit a dead end, there is a workaround using which you can rotate a Line shape using the Width and Height attributes available.
Learn how to change a diagonal line to a horizontal / vertical line in PowerPoint 2011 for Mac.

