Application sharing can be activated from any of the three views: Full Screen; Part Screen or Application Screen.
To activate an Application Sharing session :
Click on the Application Sharing button on the Live View Control Bar.
The Application Sharing window appears, select the person to whom you would like to transfer control and click OK.

A Grantor is the person giving control of his her computer.
A Grantee is the person receiving control of another user's computer.
The Grantor of an application sharing session can terminate the session at any time by:
Pressing any key on their keyboard.
Clicking on the Application Sharing button on the control bar.
Closing the Live View window that is being shared.
Other users in the meeting are not notified of an application sharing session's start. Only the Grantor and Grantee are notified.
The Grantee only has control over the area the Grantor has designated. For example, if an application is selected, the Grantee only has control over that application and nothing else.
The Grantee controls the Grantor's mouse movements. If the Grantor moves his/her mouse they "take control" away from the Grantee for as long as they are moving the mouse - in the shared window.
The Grantee cannot transfer clipboard data between their computer and the Grantor’s computer. Clipboard operations will remain within each computer.
Warning: Be sure
that you want to give control of your computer to another user! You can immediately
end a Sharing session by pressing any key on your keyboard.