[Asterisk-bsd] Need Help in changing Voice message

[Farooq Ahmed]

Hi,
Asterisk has a lot of customizable voice prompt in /var/lib/asterisk/sound
but i want to change a very well known voice message which occurs when we try to dail a number 
against dial plan
"beep beep beep The person you are calling is unavaiable, please try again."
I thought it would be availabe in the sound directory of asterisk but it is not there.
When i dial such wrong number no log appears in the asterisk cli command just get this message 
so i am not getting any idea which macro or application generating this message. 
Anybody have any idea about how to change this?
 
Thanks & Regards
Farooq
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