It's a feature that's either implemented to the mission or not. Not all MP missions have the possibility to respawn. In the ones that have it, it's done automatically. Player only needs to sit back and watch it happen.
OFPEC is not the place for gameplay questions. Only editing discussion is allowed.
I suggest you go to BIS forums at
www.flashpoint1985.com where you'll find all the info you'll ever need conserning gameplay and everything else.
#locked