You can configure settings for your optional greetings from the Greetings tab on the User Preferences Web pages. If optional greetings are not be visible to you, it means that they have been disabled at the administrator level.
To set the optional greeting to play for all calls, select All.
To set the optional greeting to play for internal calls only, select Internal.
To set the optional greeting to play for external calls only, select External.
To set the optional greeting to play for all calls, select All.
To set the optional greeting to play only when your phone is busy, select Busy.
To set the optional greeting to play only when a caller gets no answer on your phone, select No Answer.
To set the optional greeting to play at all times, select All.
To set the optional greeting to play only during office hours, select Office Hours.
To set the optional greeting to play only during non office hours, select Non Office Hours.