Some fish can switch sex more than once over a lifetime. In lizards, genetically male hatchlings can be born looking and functioning as females. In some frogs, genetically female individuals can develop into fertile males.

Source: https://www.thehindu.com/sci-tech/energy-and-environment/global-warming-is-turning-frogs-sex-reversal-into-an-extinction-risk/article71570813.ece