Communication servers use the reason code 0 as the default code for situations in which the communication server places the agent in the AUX mode automatically (for example, on login, when agents make or receive extension calls from AI/MI mode, when the agent is taken out of service due to failure to answer a ringing call) or logs the agent out (for example, during a Move Agent while Staffed operation). ASAI applications that change the agent's work mode to AUX or log the agent out without specifying a reason code will result in change to AUX or logout with the default reason code.