Super Administrators (or Global Administrators when microsites are enabled) can edit user roles from the Admin tab. The most common reason to change a user's role is when a Super (or Global) Administrator is assigning or removing Administrators from the system.
Note: You will rarely need to add Applicant or Reviewer accounts this way. Applicants are added to the system automatically when they click Apply for the first time to an opportunity. Reviewers are added to the system automatically when they are assigned their first review.
Steps to Change User's Role
1. Click the Admin tab.
2. Click the Manage Users button.
3. Search for the user. (Note: Click the magnifying glass or hit "Enter" to execute the search).
4. Click their name.
5. Click the Edit This User button.
6. Change the user's role under the Roles dropdown.
7. Click Save.