Change or add roles to a given user.
In the administrative menu, go to People.
Locate the user name of the account you want to update in the list. If it is not immediately visible, use the role, permission, status filters to narrow down the list.
Click the edit link in the row of the user account you want to update.
On the User's profile edit page, enable or disable the roles based on how you'd like to change them.
Alternatively, you can edit more user accounts in a bulk by following these steps:
Locate the names of all of the user accounts you want to update, and select them using the checkboxes.
In the Update options drop down menu, select the role you'd like to add or remove.