Does Unity have this feature or is there a way to accomplish this feature?
Very interesting feature! Sorry to say that it is not supported on a CCM/Unity installation :(
For those of you following along, here is a description of the "Leave Word" feature;
Leave Word Calling
Leave Word Calling (LWC) is a switch feature that allows people within a company to leave a prerecorded message requesting that their call be returned) by pressing a button on their voice terminal. If the caller does not have a LWC button, the caller can dial the LWC dial access code followed by the destination extension. As integrated with the DEFINITY AUDIX system, LWC does not allow the caller to leave a spoken message, but does identify who called, the time and date of the call, and extension of the caller.
The LWC feature is the quickest way to ask someone to return your call
From this doc;
Hope this helps!