The slug ‘community’ is coming from the file where the Community custom post type is registered. To change it, look in /lib/post-types.php and on line 24, change the slug from ‘community’ to ‘real-estate’.
From there you’ll need to visit Settings > Permalinks (no edits necessary, just visit the page) to flush your rewrite rules.
Keep in mind everything in your admin will still say “Community” as you’re not changing the custom post type labels or name (I really recommend not changing any of that as it’ll require additional changes throughout the widget files, etc).
As always, I recommend making changes like this on a test site and not your live website. That way, if anything goes wrong, you won’t mess up your live site.