To edit a shape first select it.
Selected Shape
Drag either of the shape's corner manipulators( 
) to change the corners or ends.
Drag any rotate manipulator 
to rotate the shape.
Drag any scale manipulator
to re-size the shape.
Drag the shape to move it.
Shape Properties Dialog
You can also edit the parameters of the shape using its properties panel as shown below. To view the properties panel first select it. Then right-click on it, then select Properties Panel from the context menu that opens.
Click the 
button to show this help topic.
Layer - Select the layer for the shape. This only applies to shapes in PCBs or Footprints.