If there is only one instructor in the course (i.e. the Course Admin), all the classes of the type Lecture have the Course Admin as the default Class In-charge.
If the course has more than one instructor, Course Admin can assign lectures to various instructors, who then become the Class In-charge.
Only a Class In-charge can add, remove, and publish activities for a lecture.
The Class In-charge can be changed any time before the lecture begins. The new Class In-charge will then have all the privileges that the previous class in-charge had. If the previous Class In-Charge had added any activities to a lecture, the new Class In-charge can edit, remove or publish any of those activities attached to the class.