After creating the new conferencing policy for users, it must be assigned. A site policy automatically applies to users and does not require this step.
1. Select Users in the navigation pane.
2. Search for a user, highlight the account, click Modify, and click Assign polices.
3. In the Conferencing policies section, select the new conferencing policy and click OK.
The Lync Server Management Shell can also be used to assign a conferencing policy to user.
Grant-CSConferencingPolicy <User's SIP Address> -PolicyName "Allow AV and Desktop Sharing"