The effect of a Disconnect action depends on the type of call flow in which it is used.
For calls within a Queued or Still Queued call flow, the action returns the call back to the queue.
For calls within other types of call flow, the action disconnects the call.
Calls reaching an action result which has no connection to another action are treated the same as if they had reached a Disconnect action. However, using a Disconnect allows you to play prompts to the caller before they are disconnected.