Marking a User Inactive (Not Enabled)
If you want to not let someone use your system anymore, but you want to keep the historical data associated with them, you can mark them inactive. This can be more convenient than deleting a user
because a) you get to keep all of their data and b) you don't have to reassign all of their data.
Do make a user inactive go to Admin > Manage Users. Then click the users name.
Change the radio button enabled to 'no'.