The filter method involves adding some custom code to your child theme functions.php to filter the permalink.

In this example we’re changing property to listing:

add_filter('realteo_rewrite_property_slug','my_custom_property_slug');
    function my_custom_property_slug(){
    return 'listing';
};
add_filter('realteo_taxonomy_property_name','my_custom_property_name');
    function my_custom_property_name(){
    return 'Listing';
};

To change “properties” archive slug use:

add_filter('realteo_rewrite_property_archive_slug','my_custom_properties_slug');
    function my_custom_properties_slug(){
    return 'listings';
};

After that change you might have 404 error on all your properties. To fix it, go to your Dashboard → Settings → Permalinks, and just click ‘Save‘ (without changing anything). That should clear permalinks table and fix that problem.