SQL & PL/SQL

with a as
(select '<?xml version="1.0"?>
<ROWSET>
  <DEPT>
    <DEPTNO>10</DEPTNO>
    <DNAME>ACCOUNTING</DNAME>
    <LOC>NEW YORK</LOC>
    <EMP_LIST>
      <EMP_ROW>
        <EMPNO>7782</EMPNO>
        <ENAME>CLARK</ENAME>
        <JOB>MANAGER</JOB>
        <MGR>7839</MGR>
        <HIREDATE>09-JUN-1981 00:00:00</HIREDATE>
        <SAL>2450</SAL>
      </EMP_ROW>
    </EMP_LIST>
  </DEPT>
</ROWSET>' from dual)
select * from a;

i want output after removing <HIREDATE> tag like this

<?xml version="1.0"?>
<ROWSET>
  <DEPT>
    <DEPTNO>10</DEPTNO>
    <DNAME>ACCOUNTING</DNAME>
    <LOC>NEW YORK</LOC>
    <EMP_LIST>
      <EMP_ROW>
        <EMPNO>7782</EMPNO>
        <ENAME>CLARK</ENAME>
        <JOB>MANAGER</JOB>
        <MGR>7839</MGR>       
        <SAL>2450</SAL>
      </EMP_ROW>
    </EMP_LIST>
  </DEPT>
</ROWSET>

Please help me