addParticipant - add a participant removeParticipant - remove a particpant promoteParticipant - Make a participant admin demoteParticipant - remove participant as admin
...
client.addParticipant('XXXXXXX-YYYYYY@c.us','ZZZZZZZZZ@c.us')
client.removeParticipant('XXXXXXX-YYYYYY@c.us','ZZZZZZZZZ@c.us')
client.promoteParticipant('XXXXXXX-YYYYYY@c.us','ZZZZZZZZZ@c.us')
client.demoteParticipant('XXXXXXX-YYYYYY@c.us','ZZZZZZZZZ@c.us')
...