Unable to end a sync partnership

I am trying to delete a sync partnership, but the delete option (from right
click on the partnership) is greyed out. I can find no way to remove it.

Originally, this sync seemed to work fine. But then the network share was
removed, and now I need to remove the sync partnership.

(Actually, there is more to the story. The share was on a Win XP computer.
I then upgraded that other computer to Vista. But at that point, the sync
partnership said "not available" and I never was able to get it to work
again.)

Thanks,
Bruce