1. A clipping path will come back to you as a single layer PSD or EPS file.
2. The clipping path file is still fully editable by you.
Here is how it works.
1) Open your psd file in photoshop
2) In the layers pallet click on the paths tab. You will see a path of the subject.
3) Click on path to highlight layer, then control/command click on the path layer to bring the visible path around your subject.
4) Click on your layers tab, click on the background layer to highlight, then click control/command J to bring your subject up on a transparent layer.
To edit your path.
1) Go back to your paths tab, click path layer to highlight then control/command click to bring your path back up.
2) Make sure the path tab is highlighted, select your pen tool hold your control/command button down and draw a box around the area you want to edit.
3) This will bring your nodes. The black nodes are the active one and will allow you to modify the clipping path on that area of your subject.