Lexmark XC6153
From the home screen, touch Settings > Fax > Analog Fax Setup > Fax Receive Settings > Admin Controls.
Configure the Fax Forwarding, Forward To, and Forward to Shortcut settings.
Apply the changes.
Lexmark CX/CS8xx_72x and XC/Cxxxx: Fax Forwarding Issues
Cannot send a fax? Changing the printer fax mode or contacting your administrator can help you solve this problem.