If you just need to replace the rope take the 2 back caps off....
These
and start pulling all the rope off.
If the rope isn't totally wasted you can wash it off real good, singe the frayed spots with a cigarette lighter, and put it back in. Or get new rope.
To reinstall..... Attach one side, twist the rope up as tight as you can (to reduce its diameter), in 2-3' sections, and start tapping it back into the groove with a clean rubber mallet. Do that all the way around to the other securing cap BUT DON'T CUT THE ROPE. After it sets awhile the rope will untwist. Once it is done relaxing THEN you can cut the rope, singe the ends, and reattach the other securing cap.