you cant

you just restart the chapter in wich the unit died without saving. you lose the level progress, but regain the character.

pretty good,unregistered 3.i was gonna say that.

lets see... how to put it... I believe they're dead. unless you restart the chapter. Or
you can hard reset(turn off GC and then turn back on) or soft reset, which is holding
start B and X for about a second, which will reset it anytime.

the other guys told the answer so stop lookin

You can bring charecters back to life by getting a staff in a chapter that has lots of
priests.If you don't kill any priests you get the staff.

Note: this staff is not called Hammenrie or how ever you spell it.