How do you Undo a "Connect as different user" to a shared printer?

I shared a printer on a XP Media Center pc and added the user id of the user
from a Vista Home pc to the XP MC machine.

Now I've removed the user id from the XP MC machine. When we go to add the
shared printer on the Vista machine, it says the share already exist with
another id, and to remove it.

The previously shared printer does not show on the vista machine, so how do
you get rid of a share to a printer when it's not showing up? Or how do you
remove the "connect as different user" connection when you can't see it?