Taken from the FF wiki
I think this will be a really useful ability for the White Mage to have, sometimes when a healer dies in a boss fight that means your whole party is going to have to start the fight over again if the boss has still a large amount of HP like say 35% left, almost dead but you're not going to kill it realistically, anyway, a white mage or any other healer could cast on themselves if they're about to die and they can be revived in a weakened state.Reraise (リレイズ, Rireizu), also known as Life 3 or Auto-Life, is a recurring White Magic spell from the Final Fantasy series. It bestows the status of the same name that automatically revives an ally the next time he or she is knocked out.
What do you think?