Preemption works with Precedence Routing to further extend the call routing capabilities of MLPP. Preemption actually disconnects an existing, lower-priority call to complete a more important precedence call. Even non-MLPP calls are treated as Routine level precedence calls, and can be preempted.

When preemption occurs, the callers on the existing call hear a tone that indicates that the system is about to preempt the call. The callers have 3 seconds to end the call before the system automatically disconnects the call. After the system disconnects the call, the system places the new call over the preempted facility.