create procedure 
reset_password( p_username in varchar2, 
                p_password in varchar2)
as
begin
   if ( USER='GEORGE' and p_username in 
                    ( 'MARY', 'BILL', 'SUE' ) )
   then
      execute immediate 
      'alter user ' || p_username || 
      ' identified by ' || p_password;
   else
      send_email_to_admin
      ( 'george trying to change ' || p_username );
      raise_application_error
      ( -20001, 'George, you cannot do that' );
   end if;
end;
/
grant execute on reset_password to george;