Course and Module Directors can directly add faculty and change the role of people in their course.
To add a new user, click Site Editor and then Add Participant. You will need to enter either the Sakai username or the e-mail used by Sakai for that person in the "Official Email Address or Username" box, then click Continue. On the next screen choose a role in the course. Then click Continue, next determine whether you want to notify the user of the access. Finally, click Finish.