In the Persona series only someone with the power of the Wild Card can switch personas. In Persona 3 and Persona 4 that ability was unique to the protagonists. However, in Persona Q: Shadow of the Labyrinth everyone can use other Personas.
Allowing other characters like Kanji who usually is limited to physical attack and lightning skills change Personas gives players more strategic options. Switching to Flauros gave Kanji a spell that inflicted shadows with sleep. Equipping Titania instead of Amaterasu allows Yukiko to use wind skills. Personas equipped by other characters level up and learn new skills just like in other Persona games.
Persona Q: Shadow of the Labyrinth comes out on June 5 for Nintendo 3DS.