1. Click the Auto Attendant phone number.
2. Click Select.
3. Choose a phone number to transfer callers to and then click OK.
4. Click OK again to save the range definition.
Tip
These two options are mutually exclusive within the Unassigned Number configuration, but keep in mind you can always use the custom greetings on an Exchange Unified Messaging Auto Attendant to also play an announcement for callers.