From a D-term phone with feature buttons for FWD and FWD-DA

To set direct forwarding:
Press SPEAKER, then press FWD, dial forwarding number, see FWD SET on display, hang up.

To cancel direct forwarding:
Press SPEAKER, then press FWD, see FWD CNCL on display, hang up.

To set delayed forwarding:
Press SPEAKER, then press FWD-DA, dial forwarding number (x1010 for voice mail), see FWD SET on display, hang up.

To cancel delayed forwarding:
Press SPEAKER, then press FWD, see FWD CNCL on display, hang up.

From a Single Line Phone or a D-term without feature buttons labeled for forwarding:

To set direct forwarding:
Lift handset and press *5, then dial forwarding number, listen for tone, hang up.

To cancel direct forwarding:
Lift handset and dial *6, listen for tone, hang up.

To set delayed forwarding:
Lift handset and dial *7, then dial forwarding number, listen for tone, hang up.

To cancel delayed forwarding:
Lift handset and dial *8, listen for tone, hang up.

NOTE: In order to perform these functions on a particular line, you must be at the phone or at a D-term where that line appears and have that line selected.