The only way to recover your lost character is to build up the Double Attack energy gauge to full, upon which they'll receive a small amount of health back. If one character loses all their health they'll teleport out while the other takes point. Use these tricks to keep your characters alive longer. Gain combos to recover a reserve character's red health faster. Don't switch back to your recovering character before they fully heal or you'll lose any remaining red health bars. If you keep your character out in the field the red health bars will slowly deplete (except with X's armor suits equipped), but if you call in your reserve character the bars will gradually turn back to green over time (speed the process up by developing the Speedy Recovery chips). If you watch your health bar carefully when taking damage, you'll spot some of it turning red.
#MEGAMAN X8 LUMINE PS2#
Press the Character Change button (default L2 on PS2 and F on PC) at any time to switch between characters, using it in times of need such as when caught by a hostile to break free. Note that you can't select a mission navigator when using one of them, and all dialog scenes between the Hunters and bosses will be skipped if using a navigator. Once you've unlocked the navigators as playable characters (see below) press Special Weapon (default Triangle on PS2 and S on PC) on the character select screen to view them. Alia will give general hints of stage layouts and enemy intel, while Layer primarily gives hints of enemy & boss characteristics and weaknesses, finally Pallette will give hints of alternate routes or hidden areas within stages. Upon selecting your team, you'll have the option of choosing one of three navigators (or none) to see you through the mission. Once X recovers new armor suits, you'll have the option of using and customizing them (in the Neutral Armor's case) or sticking with normal X without armor equipped. Much like X7 you'll have two characters to choose before tackling a mission (except the inital Noah's Park run-through).