The Path Selection* Tool selects and moves (fragments of) existing path's / vector shape mask's segments / anchor points:
In the Toolbox, select the Path Selection
Tool.
Click on a path or shape component in image window
to select it**.
Drag selected path component to move it.
To delete selected path or shape component press [Delete]
key.
To select 2 or more components shift-click (mouse-click
holding [Shift] pressed) on every one.
While multiple components selected you can align
or combine them into a single path using buttons
on the Options bar (movie).
*In Photoshop 6 and earlier versions - Path Component Selection tool. **In case the work path / vector shape layer is not currently selected, first click on a path or shape to select path / layer name; then click once more to select it's component.