code: public void revokeOwnership(Jid jid) throws XMPPErrorException, NoResponseException, NotConnectedException, InterruptedException {
          changeAffiliationByAdmin(jid, MUCAffiliation.admin, null);
      }
docs: Revokes ownership privileges from another user. The occupant that loses ownership
  privileges will become an administrator. Room owners may revoke ownership privileges.
  Some room implementations will not allow to grant ownership privileges to other users.
  
  @param jid the bare XMPP user ID of the user to revoke ownership (e.g. "user@host.org").
  @throws XMPPErrorException if an error occurs revoking ownership privileges from a user.
  @throws NoResponseException if there was no response from the server.
  @throws NotConnectedException
  @throws InterruptedException