how to change domain name – shared hosting

Bonjour!

I’m using demo.sample.com as a development site for my wordpress site sample.com. Both sites (shared hosting on Mediatemple’s Grid service) are in separate directories/folders inside the domains folder.

I want to change demo.sample.com to sample.com (ie. demo.sample.com will become the new sample.com).

If I change the 2 domain URLs (in the WordPress Address and Site Address, in Settings -> General, of demo.sample.com) to sample.com, that leaves 2 wordpress installations with the same name in the domains folder.

So before I do this, should I first rename the original sample.com (eg. to old-sample.com) before changing the 2 urls in demo.sample.com?

In this scenario, will adding a permanent 301 redirect to old-sample.com’s htaccess file (ie ‘Redirect permanent / https://sample.com’ ) point its pages to any equivalent pages in the ‘new’ sample.com?

Will this procedure correctly change demo.sample.com to sample.com?

Thanks!