Heyerdahl believed there were cultural similarities between pre-Columbian civilizations of the Andes and Polynesians because the South Americans "colonized the then-uninhabited Polynesian islands as far north as Hawaii, as far south as New Zealand, as far east as Easter Island, and as far west as Samoa and Tonga around 500 AD". (Quoting Wikipedia.) He also believed the current Polynesian population came to the islands centuries later by first going to the Pacific Northwest of the Americas and then to Hawaii before going to the rest of the Pacific.
That can't be so easily reversed.