Changing ownership of Smart Notes

We recently upgraded to V10. I was tasked with migrating all smart notes to V10. In the process, I became the 'owner' of all smart notes. My colleagues can no longer see any Notifications. In some cases, I have full editing rights of other's notifications, and in other cases I do not have editing rights, and the original publisher cannot even see them, thus no one has editing access to some of these notifications.

We have instructions that explains how to change ownership of notifications, which say to go into Content Administration, eventually select a User in the steps, and this will change owners; however, there are no users listed anymore (I can see User Groups, but not Users). In V9 we used to be able to see all users that were set up with LBI security, and now, we can't.

I am guessing once users are visible in this tool I can change ownership back. How do we get the individual users back there? Once that is done, I assume I can change ownership back?

Any other thoughts on how to change ownership of Smart Notes so that the owner has editing rights is appreciated. Thanks!