Addings dynamic 301 redirects to the .htaccess file for WordPress from sub-directories to sub-domains

.htaccess

# You need the following line before the redirects for this to work
RewriteEngine On

# 301 Redirect to subdomain no query strings attached to the end of the redirected URL
RewriteCond %{HTTP_HOST}  ^yourdomain\.com$ [NC]
RewriteCond %{QUERY_STRING}  ^page_id=10$ [NC]
RewriteRule ^site1/$ http://site1.yourdomain.com/newpage? [R=301,NE,NC,L]

# 301 Redirect to subdomain with query strings attached to the end of the redirected URL
RewriteCond %{HTTP_HOST}  ^yourdomain\.com$ [NC]
RewriteCond %{QUERY_STRING}  ^page_id=10(&.*)?$ [NC]
RewriteRule ^site1/$ http://site1.yourdomain.com/newpage?%1 [R=301,NE,NC,L]