Reincarnation Determination allows the user to reincarnate as any future individual of their choice. They retain memories and powers, even powers acquired from reincarnating as a superhuman.
Reincarnation Determination was an ability used repeatedly early on, predominantly by Wish. It was originally used to survive death at the hands of Greenday who stole the Spear of Destiny, killing Wish instantly.
Wish, however, had incorporated this into a plan devised with Elaborate Planning. He survived using this power and took the opportunity to return in a position of power; in this case, the US president.