Make any mission that have respawn.
I belive you need to try this with at least 2 real players and the rest of the squad being AI players. Or even better make 3-4 people play a mission together and then kill the team leader and see what happen when he respawn.
But you can also do the following.
Insert 1 group of soldiers and then try to play the game on a server where you choose to be the leader.
Now run 100m and throw a grenade inbetween your 2 feet, and die.
Once you respawn you should have lost your team leader status and can no longer command your team.
- Try to kill the secound in command and see if you regain control of your squad, sometimes the command of the squad are passed on to others before you the player get the command option back.