If the Outlook Voice Access feature of Exchange UM will be used with Lync Online, each subscriber access number used must be added to the Exchange UM dial plan, and also must be configured as an access number within Lync Online. Use the following procedure to configure a new subscriber number for the Outlook Voice Access feature using the online portal:
1. Log on to the Office 365 Portal.
2. On the main page, click the Admin tab at the top, and then select Exchange from the drop-down menu to open the Exchange Admin Center.
3. On the left side, click Unified messaging, and then click on UM dial plans at the top.
4. At the UM dial plans page, select the SIP URI dial plan previously created from the list, and ...