Note: Only people on the hiring team who have connected their Gmail/Outlook calendar are eligible to be organizers. Changing the organizer is available only during the event creation (not later when editing).
By default, the person scheduling the event will be set as the organizer but you can add another hiring member if needed (e.g. when you schedule interviews on behalf of your colleagues). To do so, at the bottom of the event window click the arrow icon and select the member you want as the organizer. This is the person that is able to edit the event, add attendees, etc.