You can add an alternate pager to an existing pager mailbox. If your pager mailbox is unsuccessful at contacting your primary pager after the frequency or "busy attempts" parameters have expired, the server attempts to contact any programmed alternate pager.
To add an alternate pager to an existing mailbox:
From the navigation tree, click Mailbox Maintenance > Mailboxes.
Search for a specific mailbox or click Show All to see a complete list of mailboxes.
Select a mailbox in the list, and then click Edit > Selected. The mailbox data is displayed.
On the Message Waiting tab, under the Pager message waiting Type, click the Details link.
Select Enable Alternate Pager/Telephone Number and configure as required using Message Waiting Tab parameters for reference.
Click Save.