Override

1. To preempt, manually or automatically, a prescribed procedure.

Note: For example, one might manually override a prescribed course of action programmed to occur in the event of a fault.

2. In telephony, the entering of or seizure of, a busy circuit, i.e. , an occupied circuit, by a party other than those using the circuit.

Note: For example, an attendant might override a circuit after a busy verification, or a user with a higher precedence[?] level might override a circuit.

Source: from Federal Standard 1037C and from MIL-STD-188