Moving pro theme from one subdomain to another

Not long ago, I purchased a license for the pro theme and it was installed on a Wordpress installation on my site. I've realized that the more appropriate location for the theme would actually be on another installation of Wordpress on the same site. I don't seem to be able to do this through the interface. In other words, I can't get the license to activate. What steps do I need to take to activate the license?