You may be able to use the Features menu to switch 'forward on no answer' and 'forward on busy' on or off.
Your system administrator can configure whether you can access this menu.
To do this during a call, press the PHONE key and then press Features.
To switch 'forward on busy' on or off, highlight Fwd Busy and press On or Off.
To switch 'forward on no answer' on or off, highlight Fwd No Answer and press On or Off.
To select which calls are forwarded, highlight Call type. Press Change to change the option between All Calls or External Only.
To change the destination, highlight Destination and press Edit. Enter the number and press Select.
Press Save to save any changes.