Hi Sheila,
That's a good issue that comes up in various ways. I'm not sure if
this will take care of what you need, but I whipped up a plugin [
https://github.com/patrickmj/ReassignOwnership ] that (I think)
lets the owner, admins, or supers reassign the ownership of a
collection or an item to someone else. In the edit screen, look
for the "Reassign Ownership" panel in the sidebar at the right.
It's basically untested, but if it looks useful for your needs
I'll chip away at it as I can. It's for Omeka 2.0, so that might
also be a constraint.
Nothing there for exhibits yet -- needs a little more digging
around to see if/how to implement that.
Patrick