How to turn off the is_user_logged_in check for the theme registration page?

I would like to allow a site admin to add a user to his blog through the registration page without the super admin being involved. The problem is there is a is_user_logged_in check which is redirecting the site admin if logged in, is there a way to disable this check for the registration page only, I can use current_user_can to check if the user is site admin aftre i stop the redirect