How do I change a users license from "full" to email only?

Hello Colleen,

Assuming you are working in Clarizen V6, you may go to the People module.

There you can display the detailed view. In the detailed view, please select the licensees whose license you wish to change.

Then click on the admin button a the top of your the displayed list. under the licenses button, you may revoke the users' existing licenses and assign new email licenses.