When a write-to-operator-with-reply (WTOR) is destined for a program operator application (POA) and cannot be delivered, it is rerouted to a system console using the routing codes defined in the appropriate USS message table.
When a message (not a WTOR) is destined for a program operator application (POA) and cannot be delivered, it is converted to an unsolicited message and rerouted to the primary program operator (PPO), if it is available. If the PPO is not available, the message is redirected to the system console using the routing codes defined in the appropriate USS message table.