Abstract: Automatically changing the alert state of user devices for time-based and location-based events. In response to a time-based event, such as a scheduled calendar appointment, a system transmits a signal to an associated user device to change its alert state such as from an audible ringer mode to a non-audible vibrate mode. The system can make a similar alert state change upon receiving an indication of a location-based event such as detection of the user device within a particular building geographic area. If the user device is not remote controllable to change its alert state, the system transmits a text message or audio message to the user device to inform the user of the occurrence of the time-based or location-based event.