In the example above a callback call flow was created for an individual user. The Default Callback start point can be used to create a default callback call flow for all users. If the Default Callback start point is used, it must be designed so that users have to indicate which mailbox they are accessing. In the simple call flow used above, this can be done by entering ? in the Mailbox field of the Get Mail action. The callback number is initially set through IP Office Manager.