Teachers and any administrator of a group or class can change a member's role by following these steps:

1. Navigate to your class by clicking on its name on the left menu
2. Click on the Manage icon on the top
3. Click on the Staff tab
4. Choose the member by clicking on the button as shown below
5. Click on Change Role
6. Click on Role Type and select the desired role and add title
7. Click Save on the top right