htaccess rewrite rule based on Cookie

I want to redirect the request to a different site by checking whether the cookie "MY_cookie" is set or not. If its set, redirection should happen.

This is the code that i am currently using, But not working.

RewriteCond %{HTTP_COOKIE} MY_cookie=([^;]+)
RewriteRule ^$ http://another.website.com [R=301,L,qsappend]

What is the solution. ?

Thank you