ORIGINAL: Pydpiper
I do not know about the Ten Point, but an Excalibur can be uncocked using the same device you used to cock it. However, a lot of people still carry an old arrow to shoot into the ground for that purpose.
David is talking about a rope cocker, not Excals version of the Acudraw which is detachable and called a "Crankaroo". You can use a rope cockerto uncock a10 pt I believe, but not the wind up types in either event.
The rope cockers only need half the effort, 150# pull bow=75# to cock and are much faster and quieter than the crank types. You/he may want to see if he can use one of those since they are cheap, if he needs the crank type you can always use it to uncock the bow.