The first thing you do to fold a Jane Loom with a warp on is this:
1. Release the tension (either off the back beam or the front beam)
2. Raise all harnesses so they are up.
3. Undo the screws on the side
4. Fold her down
5. Squish her arms in so you can screw them into the locked position.
6. Re-tension and engage the toggle on the back beam, so the warp is not sloppy.