I need to change the domain name of one of my slave sites to a new domain. I was advised to do the following:

1. Create a new AddOn Domain in cPanel and use the same site directory path as the existing slave site which I want to replace.

2. And then to add the new domain as the first domain in the existing site's "List of Domains" and then to click the "Yes" radio button where it says "Redirect to first domain."

Question: Doesn't this result in both domains appearing to have identical content, which is bad for SEO?

My other thought is to:

1. Create a new, separate AddOn domain with its own new directory and path.
2. Duplicate the existing slave in JMS, edit it's configuration changing the domains and paths, and then to...
3. Delete the files from the old site and put in an .htaccess file with a series of 301 redirects to the new slave site domain. I'm not sure if the site will still resolve properly if the Joomla aliases are deleted? (If not, I can remove it from the JMS and create a separate cPanel account on our server for the old domain (we have a VPS).

I'd think the latter process would avoid duplicate content, and also update all indexed search engine links, thereby preserving existing linkjuice.

Can you please let me know if I am correct in my concerns about the first method implying duplicate content for both domains?

Thanks!

Because you perform a redirection the SEO knows that the "first domain" is the one that own the content and that the other one does not have real content. In addition, you will never reach the other domain as they will be redirected to the first one.

Duplicate the website with another path is also a solution but in this case, you will have to delete the existing one (as mentioned in 3).

The (3) .htaccess is equivalent to the solution propose with the redirection in jms.
If you remove the existing Addon domain associated to the existing site then of course, the server will not more give access to the document root and its ".htaccess".
The DNS and apache configuration will be removed.

In both cases, you will avoid duplicated content as soon as you are using a redirection 301 that mean "redirect permanent"
So the Seach Engine will noticed that you have moved the content into another site.


Remember that for JMS, if you create a slave site, it must be own by the same cPanel account. You can not create a slave site that is located into another cPanel account.
You will have linux permission errors because the owner of the directories and files will be differents. There is no communication between different cPanel account.