Twig Masters

I have been editing my ini files locally and then uploading them to my server via ftp for a while now. I noticed a while back there is an option to edit settings right from the Ark server control panel using the "Modify Config" button. If I was to use this and not fill in all of the fields in it, would it change everything back to default or would it change only the settings I change or fill in? Say I want to change only the MOTD and fill in that field only. Would I need to edit all the other fields or would they stay with the settings I already have in the ini file I uploaded? Thanks in Advance