Look at the FAQs for "moving Zen Cart to a different folder" and similar phrases.

It is a very simple process. Assuming both are on the same server, you just move all the files to the desired folder and rename the filepaths in /includes/configure.php and /admin/includes/configure.php to reflect the new location.

As your site address indicates you have ZC installed in a subfolder, you would just follow the steps for "moving a site to the root".

You would first want to move the current root cart to a subfolder or otherwise archive it, so the root is essentially empty.