Change an E.164 number in Exchange Online
When you enable a user for UM and link them to an E.164 dial plan, two EUM proxy addresses are created. One contains the user's extension number and the other contains the E.164 number for the user. The extension number is used when the user calls in to an Outlook Voice Access number.
You can change the primary E.164 number that was added when the user was enabled for UM or a secondary E.164 number that was added later, along with the EUM proxy addresses for the user. The primary E.164 number you added when the user was enabled for UM will be listed as the primary EUM proxy address. Any additional secondary E.164 numbers you added will be listed as secondary EUM proxy addresses. When E.164 numbers have been changed, callers can leave voice mail for the user at all the new E.164 numbers that have been set. All the voice messages will be delivered to the same user's mailbox.
You can use the EAC or Exchange Online PowerShell to change the primary and secondary E.164 numbers for a user. You can use the Email Address page on the user's mailbox to change a primary or secondary E.164 number. However, you can't use the UM Mailbox page in the EAC to change a primary or secondary E.164 number.
You can view the primary and secondary E.164 numbers for a user by using the Get-UMMailbox cmdlet or the Get-Mailbox cmdlet in Exchange Online PowerShell.
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: 3 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 these procedures, confirm that an E.164 UM dial plan has been created. For detailed steps, see Create a UM dial plan.
Before you perform these procedures, 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 user's mailbox has been enabled for UM and linked to an E.164 dial plan. For detailed steps, see Enable a user for voice mail.
Before you perform these procedures, confirm that the E.164 number that will be assigned to the UM-enabled user is valid.
For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts for the Exchange admin center.
Use the EAC to change the primary or a secondary E.164 number
In the EAC, navigate to Recipients > Mailboxes.
In the list view, select the mailbox for which you want to change an E.164 number, and then click Edit .
On the User Mailbox page, under Email address, select the E.164 number you want to change, and then click Edit . The primary E.164 number is listed in bold letters and numbers.
On the Email address page, in the Address/Extension box, enter the new E.164 number for the user, and then click OK. If you need to select a new UM dial plan, you can click Browse.
Use Exchange Online PowerShell to change the primary or a secondary E.164 number
This example changes an E.164 number for Tony Smith, a UM-enabled user.
Before you change an E.164 number using Exchange Online PowerShell, you need to determine the position of the EUM proxy address that you want to change. To determine the position, use the $mbx.EmailAddresses command. The first EUM proxy address is the default (primary) E.164 number and it will be 0 in the list.
$mbx=Get-Mailbox tony.smith $mbx.EmailAddresses.Item(1)="eum:+14255550123;phone-context=MyE.164DialPlan.contoso.com" Set-Mailbox tony.smith -EmailAddresses $mbx.EmailAddresses