When forwarding a call, the user must spell by name the person to whom the call is being forwarded. While addressing messages, subscribers can switch between spelling the name and entering the extension by pressing # twice (##).
To reverse the search option on call handler to dial-by-extension, Open System Admin in Unity (WEB/SA). Go to Subscriber > Conversation. Under Identify a Subscriber by Option , select Entering the Extension.
Depending on how Cisco Unity is set up, subscribers can address messages to other subscribers by spelling the recipient name or entering the recipient phone extension. If desired, you can disable addressing by spelled name for all subscribers on each Cisco Unity server by unchecking the Enable Spelled Name Search in the Cisco Unity Administrator on the System > Configuration > Settings page.