PARTNER Messaging provides four General Mailboxes—one for each Automated Attendant.
The General Mailbox Owner is the extension whose Message Waiting Light is turned on whenever a message is placed in the General Mailbox. The factory setting for all General Mailbox Owners is extension 10. You can program a different General Mailbox Owner for each General Mailbox or you can have the same owner for all the General Mailboxes.
Refer to PARTNER Messaging Planning Planning Form 1 System Parameters for the General Mailbox Owner extension(s) identified for your site.
To program the General Mailbox Owner(s):

Procedures
Programming System Language Mode and System Language
Programming Maximum Extension Length
Programming Call Answer Service Operator Extension