3 roles you can play:

Application Owner

An application owner is a person who shares an application or desktop(all applications except the system related ones). As an application owner, you can grant editing right of your shared application/desktop to other viewers, but you will always own the editing right to the shared application/desktop regardless of whether you have granted the editing right to anyone. The shared application/desktop resides on the application owner’s computer.
As an application owner, you can exchange roles with any of the viewers. By seleting a viewer to be the next application owner, you become a view yourself. And this selected viewer becomes the new application owner, then he has to share his own application/desktop with viewers.

Editor

An editor is a person who has received "editing right" from the application owner.
As an editor, you can edit the shared application on the application owner’s computer.  All changes made will reside on the application owner’s computer.

Viewer

A viewer can only watch the application owner and the editor work.