When you select an object on a slide, a handle with a green end on it appears at the top center of the object. This is the rotation handle, and it can be used to rotate any object on a slide. The rotation handle enables you to revolve an object around a center point.
To rotate an object, do the following:
The Draw menu (on the Drawing toolbar) also enables you to rotate or flip an object. You can flip an object horizontally left or right or flip the object vertically from top to bottom. To flip an object, click the Draw button on the Drawing toolbar and then point at Rotate and Flip . Select either Flip Horizontal or Flip Vertical from the menu that appears.