Scenario:

Station keys are set to(Station is DS-5021D/24C):

Key 1 - Feature = CALL | Extension 1
Key 2 - Feature = CALL | Extension 2
Key 3 - Feature = DT | Extension = 701(trunk)
Key 4 - Feature = DT | Extension 702(trunk)

The user is the receptionist. When the user picks up the handset and hits line Key 3, the trunk line is now active for that call but the line key 1 (CALL) key is still being used and is lit up green. Is there a way to have the line key 1 no longer active after the user dials into the trunk line key 3? The user does not want to have one of the internal CALL lines taken up for an outbound call. Is this possible? They have a PRI. Please let me know if I need to clarify the scenario further. Thank you in advance.