There are many instances when an assistant will create events for a supervisor or a department member. The assistant is creating the event but does not want to be the "organizer".
In order for you to create an event and have someone else be the "organizer":
1) You must have "Make Changes and Manage Sharing" access to the calendar. You cannot grant yourself access; the calendar owner must do this. Directions can be found here.
2) When you create the event, you must change the calendar to the "organizer's" calendar, not your own.
3) Finish creating the event. Now that someone else is the organizer of the event, they can control all aspects of the event.