When you share an aricle on Facebook, Facebook crawls the url, then saves and displays the meta title and description.  You can change Meta Titles and Meta Descriptions for your articles, but the changes will not always show up immediately on Facebook. Click to review how to change Meta Titles and Descriptions.  There will always be a lag of up to several days before the changes are displayed.  

You can test how your new meta title and/or description will look by using this tool.