When you want to change a field name, it's enough to change "Label". This is what's displayed on your site. Please don't change "Name" because you'll need to change it in template code as well. In an example, if you change the name of "property-id" you'll need to change it in 4 places in template files:
/templates/sparky_framework/html/com_content/article/default.php
/templates/sparky_framework/html/mod_articles_category/homesrandom.php
/templates/sparky_framework/html/mod_articles_category/homesrecent.php
/templates/sparky_framework/html/mod_articles_popular/homespopular.php
Other fields may have references in different files. You should use a code editor (such as Sublime Text) and search template folder for the old field name (i.e. "property-id") and change it everywhere.
Best regards,
Milos
