I am selling my PL products on Amazon UK via FBA. I am enrolled in Brand Registry and want to start selling FBA in the USA. What is the best way to list my products and transfer my reviews to my US account? Really hoping I don’t have to list them all again from scratch… not getting much help from Amazon support on this. Thank you 
If the listings don’t already exist, then your only option is to create them.
Ensure that you use the same brand name and EAN number for each listing. They will then pick up the same ASIN.