User accounts are managed on the Planners and Helpers tabs found by clicking on the People navigation link. Security level 3 is required to manage Planners. Level 2 Planners and Team Leaders (of any security level) can manage Helper accounts.

Planners and Helpers can be converted back and forth as necessary by clicking on the pencil icon to the right of the person's name. Once there, you can use the "User Type" drop down to select a new type for the user.  Security level 3 is required to convert Planners to/from Helpers.

The Master Account cannot be deleted, but the account designated as a master account can be first changed, then the previous master account can be changed.