How to make a switching character mechanic similar to Final Fantasy XV?

Hi! My name is Rui and I’m working on this Project that involves a team of five main characters going on a journey to save the world. So one of the features I wanted to implement on the game was the ability to switch between this 5 characters mid-combat. Imagine that I’m fighting a boss with charanter_1 and I wanted to switch to character_2 because of specific stats that could help on the battle how could I set up a system that allows me to do that on the press of a button. Keep in mind that my goal is that when I’m fighting with one character the other 4 remaining keep on fighting the boss.
Appreciate any help from the community :smiley: