Change the UM dial plan in Exchange Online
You may need to move a user who is enabled for Unified Messaging (UM) to a different UM dial plan or change the dial plan that's associated with the user. For example, you might want to move a UM-enabled user from a Telephone Extension dial plan to a SIP URI dial plan.
To change the UM dial plan, you'll have to disable the user for Unified Messaging and then enable the user for Unified Messaging on the new UM dial plan. This is because different dial plans may have different settings and requirements, such as different extension lengths or different URI types. For example, SIP URI dial plans require a SIP Resource Identifier to be assigned to each UM-enabled mailbox, but Telephone Extension dial plans don't. Also, each UM mailbox contains references to both the UM dial plan and the UM mailbox policy. The UM mailbox policy, in turn, contains references to the UM dial plan. If you change the primary proxy address for a UM-enabled user to point to a different dial plan, the UM mailbox is in an inconsistent state.
For additional management tasks related to users who are enabled for voice mail, see Voice mail-enabled user procedures.
What do you need to know before you begin?
Estimated time to complete: 10 minutes.
You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "UM mailboxes" entry in the Unified Messaging Permissions topic.
Before you perform this procedure, confirm that a UM dial plan has been created. For detailed steps, see Create a UM dial plan.
Before you perform this procedure, confirm that a UM mailbox policy has been created. For detailed steps, see Create a UM mailbox policy.
Before you perform these procedures, confirm that the existing Exchange recipient is enabled for Unified Messaging. For detailed steps, see Enable a user for voice mail.
For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts for the Exchange admin center.
Step 1: Create the new UM dial plan
If you're migrating UM-enabled users to Microsoft Office Communications Server 2007 R2 or to Microsoft Lync Server, you must first create a SIP URI dial plan.
For detailed instructions, see Create a UM dial plan.
Step 2: Disable the user for Unified Messaging
For detailed instructions, see Disable voice mail for a user.
Step 3: Enable the user for Unified Messaging on the new UM dial plan
If you're moving users to an environment with Office Communications Server 2007 R2 or Lync Server, you must also include a SIP Resource Identifier for the user when you enable them for UM. You must also select the UM mailbox policy that's associated with a SIP dial plan.
For detailed instructions, see Enable a user for voice mail.