I've only the envato purchase code

By the way, I have the purchase code to update a site theme that I was passed by an agency. How can I update the theme if I only have this code and do I have the theme downloaded in my envored account? Thank you. Valeria

The purchase code will only help if the theme manages updates Etc. Automatically in theme options.

There is no way to transfer the ability to download items from other accounts.