It should be enabled by default, If you go to Voice > Stations > Operator Group You can see what members are in the operator group. If you click the VM Settings tab you will see the option for VM Operator Assist # which is what extension is used while a user is leaving voicemail to exit out to operator. Hope that helps. If you can’t see picture via email, then go to the website and you can see it there. Let me know if you have any further questions.
-Mark
