If you ever need to move one (or more) subdirectories, but not an entire site over to a new webserver, and you want to redirect the traffic, here’s how you can do it:
RewriteEngine On
RewriteRule ^directory_name(.*)$ http://www.example.com/directory_name [R=301,NC,L]
If you have multiple virtual hosts on the site, you might want to specify which host name’s directory_name should get sent to new server www.example.com
RewriteEngine On
RewriteCond %{HTTP_HOST} ^markcerv.com$ [OR]
RewriteCond %{HTTP_HOST} ^www.markcerv.com$
RewriteRule ^directory_name(.*)$ http://www.example.com/directory_name [R=301,NC,L]