We have recently decided to implement the Attendant Console. In order to do this, we had to remove the DN from the receptionist's phone so we could use it for the Pilot Number. I tried to create the Pilot Number, but received the message that the number was in use. I have done several searches on phones, route patterns and translation patterns, but cannot find it anywhere. I am suspecting that it was not correctly removed from the database. Has anyone had this issue or know how to correct it.
You might be running into this "Unassigned DN" issue. Have a look;
CallManager 4.x: Delete Unassigned Directory Numbers Configuration Example
Cisco CallManager 4.x has a new concept called Unassigned Directory Numbers (DNs). When a DN gets removed/updated from a device or a phone gets deleted, the associated DNs are not removed from the Cisco CallManager database as in earlier versions. They still exist in the Cisco CallManager database as Unassigned DNs. You can see a list of DNs that are not associated with phones in the Route Plan Report menu option.
Note: In Cisco CallManager releases earlier than 4.0, DNs were automatically deleted when a device was deleted. Because line group support is a feature of Cisco CallManager Release 4.x, keeping unassigned DNs is a requirement.
From this good doc;
Hope this helps!