When a Schoolyard Pick is presented to the castaways, the opportunity to forge a stronger (or weaker) team is made. There is no one way to form new tribes, and several methods have been used.
In Survivor: Thailand, Jeff announced at the start of the game that local tradition dictates that the eldest are of the highest importance, so it was only fair if they chose the tribes. Jan Gentry and Jake Billingsley were the two oldest members, therefore they selected the two tribes.
Survivor: Cook Islands featured a Schoolyard Pick at the final 18. There were two sets of captains (2 men, 2 women). They would then select someone of a different ethnicity, who would then select someone else from a different ethnicity and so forth until each ethnic group was evenly represented on their tribe. The captains would all then break an egg at the same time to reveal who was on which of the two new tribes.
Survivor: Fiji featured a Tribe Switch at final 13. Earl Cole and Edgardo Rivera stepped up to be the two captains, then a Schoolyard Pick took place, requiring castaways to select someone from the opposing tribe. After two teams of six were chosen, Lisi Linares was left unpicked and sent to Exile Island. In the end the captains drew rocks to determine which team would become the new Moto tribe, living on the luxurious camp.
In Survivor: Micronesia the tribes were rearranged at the final 16. The remaining contestants were told to pick a colored rock to determine team captains, then a Schoolyard Pick took place in the similar style of Fiji, mixing up the fans and favorites.
At the start of the competition in Survivor: Gabon, the castaways introduced one another and in a similar fashion to Thailand, the two eldest castaways, Bob Crowley and Gillian Larson, were tasked to select the first members of their tribe, and then in the same style of Palau and Panama until no contestants were left to be picked.
Also in Survivor: Gabon, a Tribe Switch took place at final 15. The old Fang and Kota were asked to rank their members based on importance. The highest ranking ones, Matty Whitmore and Marcus Lehman, would be the captains for the Schoolyard Pick. Similar to the ones in Fiji and Micronesia, both tribes mixed up, leaving Sugar Kiper as the unpicked person who would be sent to Exile Island.