Promote’ feature can be used to promote members to co-leaders or if you want to hand the leadership over to one of your co-leaders.
To do this, tap on an orange button next to the player’s name and tap on “Promote” and confirm.
You can reverse this action by using ‘Demote’ feature but only as a leader to demote a co-leader.
If you hand over the leadership, the only way to get it back is to convince the current leader to return it.