Why? Do you want a staging site for testing?
If so, the easiest way to do it is set up the new site, have both sites share an S3-compatible bucket for backups and just restore the backup on the other site.
You can do that if you want, but there are a bunch of steps in changing hostnames, and restoring a backup is much easier. The rsync way involves moving less data around (in some ways) and lets you move to a an up-to-date OS (which you presumably don’t need to do).
So, sure, you can do that (if the host was shut down when the image was made), then edit the hostname in your app.yml and rebuild. It’ll still be easier to restore the most recent backup, but if you prefer, you can follow these steps Change the domain name or rename your Discourse