Modifying Shape Edges
You can also select the line between two points and move the edge of the shape without
affecting the rest of the shape.
To move a shape edge
With the Edit Points tool active, click any edge of a shape object.
The control points on either side of the line are selected.
Drag the line segment.
The distance between the two points remains constant, but the line can be moved freely.
Press Shift to constrain the movement horizontally, vertically, or diagonally.
To release the selection, click anywhere outside the selection, or choose a different tool
in the toolbar.