If however, you'd like to rebuild the site on your currently online site, you can do that too.
use for example a passwort protect plugin like this:
https://wordpress.org/plugins/knock-first-password-protection/
You could even create a new LocalWP site, then use one of the plugins i mentioned above to copy your online site over to a local site.
And then build your new site online, replacing the old site.
This way you would still have your old site as reference locally!