Turn Back Hands of Time

Shipwrecked and Single doesn't give the player a lot of time to become a productive adult before turning into an elder. So most players will either go to the location where the creepy shaman was found or they have their Sim earn the Concoction Junction as a career reward being a Gatherer. Then they can concoct and drink the Life Elixir to extend their lives. This way, the Sim adult can go back to day one as an adult. As an elder, this takes the Sim back to day one as an elder.

However, if you really want to turn back the hands of time, an elder Sim can visit the Temple of Tuzu on Felicity Island, drink from the chalice to skip back a generation to become an adult again. By doing this, for example, the Chief and his wife will look much different as adults, as shown in the images below. They can then have babies (again) and start all over as adults. Unfortunately, this option is not available on Wanmami Island.

Manaves as Elders	Chalice at Temple
Fangaloka Manave and Huhana Manave as adults

Yes, Chief Fangaloka's eyebrows are blond and Huhana's hair is red under that white wig. Who Knew?