You can access your mailbox from anywhere by dialing one of the Messaging access numbers (See Messaging Access Number) or dialing the Automated Attendant, if it has been configured to allow access to the Messaging system, in your organization.
the Messaging access number (external) from any other phone and press the pound key (#).
If you use somebody else's phone from within your organization, who also has a Messaging mailbox, then press * after dialling the Messaging Access Number, to cancel the automatic login based on that phone's extension and proceed with the remaining steps.
the Automated Attendant number and press the pound key (#).
The system announces your name and prompts you to enter your password.