FortiVoice delivers integrated calling, conferencing, chat and fax.
Article Id 190924
This article explains how to enable call forward either by the GUI or through phone menu settings.

FortiVoice Enterprise 3.x, FortiFone or softphone

Enabling Call Forward from the GUI

1)  Go to Extensions > Preferences > and select the Extension number which should be forwarded.

Select option “call forward” and set extension to where the call will be forwarded.

To disable the call forwarding simply uncheck the “call forward” option

Enable call forwarding using phone settings

1) Go to the phone and dial:


2) Set call forward

Dial *71 followed by a code to set user’s call forward: 1 to enable, 0 to disable, and 9 to change the forwarding number.

That is:

*719 (audio to set the number to be forwarder) -> set the number
*711 -> to enable (audio confirmation of forward enable and the number to be forwarded)
*710 -> to disable (audio confirmation of forward disable)

To change the number to be forwarded repeat the steps:

*719 -> to set the new number (the last setting will be replaced.)

In parallel the forward changes must be validated in the GUI or a forward applied as well.

Extension > extensions > preference > extension number | forward field