Mathf.Lerp not working, why?

T$$anonymous$$s is a snippet of the code where Mathf.Lerp isn't working:

 if(distAway != origDA){
         //    Debug.Log(distAway);
             Mathf.Lerp(distAway, origDA, Time.deltaTime * 30f);
         //    Debug.Log(distAway);
             if(distAway >= origDA - 0.2f)
                 distAway = origDA;
         }

The console prints out the values for 'distAway' before and after the lerp function w$$anonymous$$ch remains the same. 'origDA' is NEVER changed, and is always equal to '8' and prints out '8' in the console if I write out Debug.Log(origDA). 'distAway' is less than 'origDA' and is meant to lerp to 'origDA'. Why isn't it running? It's reac$$anonymous$$ng the function; 'distAway' isn't equal to 'origDA'. What's stopping the Mathf.Lerp function from working?