That should do. Just make sure the COS you are editing is the one that's applied to the user mailboxes and once you uncheck the below under COS it should return to the normal touch tone conversation:
Allow Access to Advanced Features
Allow Users to Use Voice Recognition
For voice recognition to work its enabled under the COS and under user mailbox (under the User Mailbox>Phone Menu) as per below. Only then the voice recognition is enabled if one is not done it will not work:
But once you disable the voice recognition under the COS - it automatically returns the phone menu input to the classic touch tone conversation.
-Terry
Please rate all helpful posts and mark the thread as answered if you have no other queries.