Although you can change the order of shapes or any other slide objects using the conventional Send to Back and Bring to Front options in the Arrange gallery, you can do reordering in a much intuitive way in PowerPoint 2011 for Mac. We call this new technique Dynamic Reordering, and this works by dragging shapes to the required positions in a special reorder view.
Learn about Dynamic Reordering of shapes and other slide objects in PowerPoint 2011 for Mac.

