There are few ways to exit a Screen Sharing session at any time during a conference. The first is to return to your Online Meeting Room and click 'Stop sharing' that will appear in the center of your Online Meeting Room inside a red box.

Each time you initiate a Screen Sharing session you will also see a message at the top of your window. To exit a Screen Sharing Session you can also click the blue 'Stop Sharing' button located on this message bar.

Finally hitting 'Share' in the menu at the bottom of your screen will also end the session.