All new Bombplates sites have a canonical url along the lines of someband.bombplates.com. However, the earliest sites did not do this; we let the band pick their own canonical url (e.g. someband.com).
99% of functionality works like this. The one exception is that old sites can't change their theme. They will get an error saying "There is a critical error in your site configuration! Please contact support." Should this happen, the user will have to contact us, wherein we will update their site.
For our instructions, we'll be moving a band called somebandmusic.com to someband.bombplates.com (for early sites, the subdomain is always the first 8 characters of their selected domain)
Log into bands2.bombplates.com
$ cd /var/www/html/sites
$ mv www.somebandmusic.com someband.bombplates.com
$ sudo vim /etc/httpd/conf.d/bombplates.conf
Remove the old entries for someband.bombplates.com and www.someband.com
Add
<VirtualHost *:80>
ServerAdmin info@somebandmusic.com
DocumentRoot /var/www/html
ServerName someband.bombplates.com
</VirtualHost>
<VirtualHost *:80>
ServerName www.somebandmusic.com
ServerAlias somebandmusic.com
RewriteEngine On
RewriteOptions inherit
ProxyRequests Off
ProxyPreserveHost Off
ProxyPass / http://someband.bombplates.com/
ProxyPassReverse / http://someband.bombplates.com/
ProxyPassReverseCookieDomain .bombplates.com www.somebandmusic.com
</VirtualHost>
Restart httpd
# /etc/init.d/httpd restart
Update the HOSTS file
# vim /etc/hosts
127.0.0.1 someband.bombplates.com
Log into the someband.bombplates.com/user
go to someband.bombplates.com/admin/settings/file-system
Update the file system path to sites/someband.bombplates.com/files
Go to someband.bombplates.com/admin/build/themes
Find LiveSite; set it to active and default; submit the form.
Update the file paths in the database
Get DB credentials from sites/someband.bombplates.com/manual_db.php
Flush the cache
Alert the user that their site is fixed