Hi, brand new to Unreal editor, so n00b question here…
After clicking Build, I am unable to see subsequent changes to my lights in the viewfinder. I expected that changing any light settings would deprecate the built lighting and it would go back to realtime updates. I am sure I am missing something simple here.
Thanks in advance…
Welcome in the UE community 
You can always see your changes in realtime -> e.g when you move an object the shadows moves with it. But you can just see the “end result” when you build the light or set all lights to “moveable” (= dynamic). e.g So it could be that after you have build your light, the shadows of your meshes will be pretty bad -> then you will have to increase the lightmap resolution
When you move something after the light build you will have to rebuild it, otherwise e.g shadows will stay where they are
Hey man, thanks for the quick response and the welcome!
The issue I was having, now that I think I can explain it better after doing more research and looking into the things you mentioned, was that I wanted to unbake the built lighting so that I could continue iterating. It looks like World Settings>Lightmass>Force No Precomputed Lighting does just that!