I'm not entirely sure what you mean by "reverse" tree. So I've put some examples of the recursive WITH below - they might help with what you are trying to achieve
SQL> with EACH_LEVEL (empno, name, mgr) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr
6 from scott.emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr
13 from scott.emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 select *
17 from each_level;
EMPNO NAME MGR
---------- ---------- ----------
7839 KING
7566 JONES 7839
7698 BLAKE 7839
7782 CLARK 7839
7499 ALLEN 7698
7521 WARD 7698
7654 MARTIN 7698
7788 SCOTT 7566
7844 TURNER 7698
7900 JAMES 7698
7902 FORD 7566
7934 MILLER 7782
7369 SMITH 7902
7876 ADAMS 7788
14 rows selected.
SQL> with EACH_LEVEL (empno, name, mgr, hier_level) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr, 1 hier_level
6 from scott.emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr, hier_level+1
13 from scott.emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 select *
17 from each_level;
EMPNO NAME MGR HIER_LEVEL
---------- ---------- ---------- ----------
7839 KING 1
7566 JONES 7839 2
7698 BLAKE 7839 2
7782 CLARK 7839 2
7499 ALLEN 7698 3
7521 WARD 7698 3
7654 MARTIN 7698 3
7788 SCOTT 7566 3
7844 TURNER 7698 3
7900 JAMES 7698 3
7902 FORD 7566 3
7934 MILLER 7782 3
7369 SMITH 7902 4
7876 ADAMS 7788 4
14 rows selected.
SQL> with EACH_LEVEL (empno, name, mgr, hier_level, padding) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr, 1 hier_level, '' padding
6 from scott.emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr, hier_level+1, '**'||padding
13 from scott.emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 select *
17 from each_level;
EMPNO NAME MGR HIER_LEVEL PADDING
---------- ---------- ---------- ---------- ----------------------------------------
7839 KING 1
7566 JONES 7839 2 **
7698 BLAKE 7839 2 **
7782 CLARK 7839 2 **
7499 ALLEN 7698 3 ****
7521 WARD 7698 3 ****
7654 MARTIN 7698 3 ****
7788 SCOTT 7566 3 ****
7844 TURNER 7698 3 ****
7900 JAMES 7698 3 ****
7902 FORD 7566 3 ****
7934 MILLER 7782 3 ****
7369 SMITH 7902 4 ******
7876 ADAMS 7788 4 ******
14 rows selected.
SQL> with EACH_LEVEL (empno, name, mgr, hier_level, padding) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr, 1 hier_level, '' padding
6 from scott.emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr, hier_level+1, '**'||padding
13 from scott.emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 SEARCH BREADTH FIRST BY EMPNO SET IDX
17 select *
18 from each_level;
EMPNO NAME MGR HIER_LEVEL PADDING IDX
---------- ---------- ---------- ---------- ---------------------------------------- ----------
7839 KING 1 1
7566 JONES 7839 2 ** 2
7698 BLAKE 7839 2 ** 3
7782 CLARK 7839 2 ** 4
7499 ALLEN 7698 3 **** 5
7521 WARD 7698 3 **** 6
7654 MARTIN 7698 3 **** 7
7788 SCOTT 7566 3 **** 8
7844 TURNER 7698 3 **** 9
7900 JAMES 7698 3 **** 10
7902 FORD 7566 3 **** 11
7934 MILLER 7782 3 **** 12
7369 SMITH 7902 4 ****** 13
7876 ADAMS 7788 4 ****** 14
14 rows selected.
SQL> with EACH_LEVEL (empno, name, mgr, hier_level, padding) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr, 1 hier_level, '' padding
6 from scott.emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr, hier_level+1, '**'||padding
13 from scott.emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 SEARCH DEPTH FIRST BY EMPNO SET IDX
17 select *
18 from each_level;
EMPNO NAME MGR HIER_LEVEL PADDING IDX
---------- ---------- ---------- ---------- ---------------------------------------- ----------
7839 KING 1 1
7566 JONES 7839 2 ** 2
7788 SCOTT 7566 3 **** 3
7876 ADAMS 7788 4 ****** 4
7902 FORD 7566 3 **** 5
7369 SMITH 7902 4 ****** 6
7698 BLAKE 7839 2 ** 7
7499 ALLEN 7698 3 **** 8
7521 WARD 7698 3 **** 9
7654 MARTIN 7698 3 **** 10
7844 TURNER 7698 3 **** 11
7900 JAMES 7698 3 **** 12
7782 CLARK 7839 2 ** 13
7934 MILLER 7782 3 **** 14
14 rows selected.