Yes, you can manually change the Affiliation/Role of any registered user.
Go to Data Studio, and in the search bar (top-right hand side), enter the name of the the person who's Role you want to change.
Select the check box beside the name. You’ll see a few options appear on the top. Take the mouse icon on the one that says Update Info, and click Edit Affiliation.
You can change the affiliation of this person from the pop-up that appears.