select name_1, surname_1 from source_table
union all
select name_2, surname_2 from source_table

CREATE TABLE PIVOT_SRC
(
  NAME_1     VARCHAR2(4000 BYTE),
  NAME_2     VARCHAR2(4000 BYTE),
  SURNAME_1  VARCHAR2(4000 BYTE),
  SURNAME_2  VARCHAR2(4000 BYTE)
)

INSERT INTO PIVOT_SRC VALUES('n1','n2','c1','c2');
INSERT INTO PIVOT_SRC VALUES('n3','n4','c3','c4');

CREATE TABLE PIVOT_TGT
(
  NAME     VARCHAR2(4000 BYTE),
  SURNAME  VARCHAR2(4000 BYTE)
)

Name, Surname
n1,   s1
n2,   s2
n3,   s3
n4,   s4

SQL> col name format a10
SQL> col surname format a10
SQL> with
  2    row_gen as ( -- as many lines as you want to split the rows
  3      select level line from dual connect by level <= 2
  4    )
  5  select decode(line, 1, name_1, 2, name_2) name,
  6         decode(line, 1, surname_1, 2, surname_2) surname
  7  from pivot_src, row_gen
  8  /
NAME       SURNAME
---------- ----------
n1         c1
n3         c3
n2         c2
n4         c4

4 rows selected.

SQL> col name format a10
SQL> col surname format a10
SQL> WITH DATA AS(
  2  SELECT name_1||','||name_2 text1, surname_1||','||surname_2 text2 FROM PIVOT_SRC
  3  )
  4  SELECT
  5         trim(regexp_substr(t.text1, '[^,]+', 1, lines.COLUMN_VALUE)) name,
  6         trim(regexp_substr(t.text2, '[^,]+', 1, lines.COLUMN_VALUE)) surname
  7  FROM DATA t,
  8    TABLE (CAST (MULTISET
  9    (SELECT LEVEL FROM dual CONNECT BY LEVEL <= regexp_count(t.text1, ',')+1)
 10                 AS sys.odciNumberList
 11                )
 12          ) lines
 13  /

NAME       SURNAME
---------- ----------
n1         c1
n2         c2
n3         c3
n4         c4

SQL>