Call forwarding is not a type of service available on shared or multiple lines. In that case, the Reject soft key is replaced with a Silence soft key, and the Forward soft key is absent as well. The Silence soft key will stop the ringing for that incoming call. However, call forwarding is local to the phone, so it’s possible to override it in the Polycom 650 server settings. You’ll need to get in touch with your system administrator and ask them to enable call forwarding or perform a warm transfer.