To modify an exisiting users permissions a Client Administrator can update the User Configuration and change the Users role to the desired level.
Please refer to Types of Users - Roles & Permissions article for role definitions.
From [USERS] menu, search for the User you want to update and click [Edit] to display the User Configuration window.
In User Configuration, select the [PERMISSIONS] menu tab.
Change the [User Role] to the desired role to modify the users permissions.
Final step is to click [Save User] to save the changes for the user.
TIP: The updated user should logout/login to enable the new permissions.