code: public void revokeAdmin(EntityJid jid) throws XMPPErrorException, NoResponseException, NotConnectedException, InterruptedException {
          changeAffiliationByAdmin(jid, MUCAffiliation.member);
      }
docs: Revokes administrator privileges from a user. The occupant that loses administrator
  privileges will become a member. Room owners may revoke administrator privileges from
  a member or unaffiliated user.
  
  @param jid the bare XMPP user ID of the user to revoke administrator privileges
  (e.g. "user@host.org").
  @throws XMPPErrorException if an error occurs revoking administrator privileges from a user.
  @throws NoResponseException if there was no response from the server.
  @throws NotConnectedException
  @throws InterruptedException