Ahh.. I see now. I'd say that you will need to reach out to Google Support then. PR is not a state, it's a territory and so is still it's own country. I see that it instructs you to create a new location when the country/region needs changed (as is the case here) - but I wouldn't do that as it would create another listing. If you go through support, they may have you create the new location, but they should also help merge as well so you don;t lose any reviews.