You can forward all calls, forward calls when the phone is busy, or forward calls when there is no answer.

To forward or unforward calls:

STEP 1 Press Setup.
STEP 2 Scroll to User Preferences and press Select.
STEP 3 Select Call Preferences.
STEP 4 Highlight Call Forwarding.
STEP 5 Press the Right Arrow key to toggle call forwarding On (checked) or Off (unchecked).
STEP 6 Press Set.

Forwarding Calls to a Single Number

STEP 1 Press Setup.
STEP 2 Scroll to User Preferences and press Select.
STEP 3 Select Call Preferences and scroll to Forward All Number.
STEP 4 Enter a number to where all calls are to be forwarded; for example, your voice mailbox, another extension, or an outside line. If forwarding calls to an outside line, be sure to enter any steering digits, access codes, or area codes required.
STEP 5 Press Set.

Forwarding Calls When Your Phone is Busy

STEP 1 Press Setup.
STEP 2 Scroll to User Preferences and press Select.
STEP 3 Select Call Preferences and scroll to Forward Busy Number.
STEP 4 Enter vm for voice mail, or a number where to forward all calls; for example, another extension, or an outside line. If forwarding calls to an outside line, be sure to enter any external line access and area codes required.
STEP 5 Press Set.

Forwarding Calls When You Do Not Answer the Phone

STEP 1 Press Setup.
STEP 2 Scroll to User Preferences and press Select.
STEP 3 Select Call Preferences and scroll to Forward No Ans Number.
STEP 4 Enter vm for voice mail, or a number where to forward all calls; for example, another extension, or an outside line. If forwarding calls to an outside line, be sure to enter any external line access and area codes required.
STEP 5 Press Set.

Delaying Call Forwarding When there is no Answer the Phone

STEP 1 Press Setup.
STEP 2 Scroll to User Preferences and press Select.
STEP 3 Select Call Preferences and scroll to Forward No Ans Delay.
STEP 4 Enter the number of seconds to delay forwarding calls when there is no answer at your phone.
STEP 5 Press Set.