Amazon Sellers Account Ownership Transfer

I have been looking for a clean, aged US Amazon Sellers account and I have someone ready to sell, but the account is registered as a sole proprietorship using his ss # (US) and the email associated with the seller's account is tied to his main buyer's account. He won't part ways with his personal buyer's account. I know admin access can be given to another account to "manage" the seller's account but how can I go about transferring ownership and changing the email? It's a handmade fba account btw. Any help would be much appreciated.

Nobody has info on this? I'm willing to pay for details.