Need to delete the row from the table which is duplicate on entire row - response (3) by CarlosAL

This has been asked and answered over and over...
Your mileage may vary, but in the end you can apply some variations of:
 
 BTEQ -- Enter your SQL request or BTEQ command:
SELECT * FROM CARLOS.PRUEBA03 ORDER BY 1;BTEQ -- Enter your SQL request or BTEQ command:
SELECT * FROM CARLOS.PRUEBA03 ORDER BY 1;

 *** Query completed. 9 rows found. 2 columns returned.
 *** Total elapsed time was 1 second.
          ID_N  C_TXT
--------------  -------------------------
            1.  A
            1.  A
            2.  B
            2.  B
            2.  B
            3.  C
            4.  F
            4.  E
            4.  D
 BTEQ -- Enter your SQL request or BTEQ command:
INSERT INTO CARLOS.PRUEBA03
SELECT -1*ID_N, C_TXT
  FROM CARLOS.PRUEBA03
 GROUP BY ID_N, C_TXT HAVING COUNT(1) > 1
;
 *** Insert completed. 2 rows added.
 *** Total elapsed time was 1 second.
 BTEQ -- Enter your SQL request or BTEQ command:
DELETE
  FROM CARLOS.PRUEBA03 a
 WHERE EXISTS (SELECT NULL
                 FROM CARLOS.PRUEBA03 b
                WHERE B.ID_N < 0
                  AND b.ID_N = -1 * a.ID_N
                  AND b.C_TXT = a.C_TXT )
;
 *** Delete completed. 5 rows removed.
 *** Total elapsed time was 1 second.
 BTEQ -- Enter your SQL request or BTEQ command:
UPDATE CARLOS.PRUEBA03
   SET ID_N = -1*ID_N
 WHERE ID_N < 0
;
 *** Update completed. 2 rows changed.
 *** Total elapsed time was 1 second.
 BTEQ -- Enter your SQL request or BTEQ command:
SELECT * FROM CARLOS.PRUEBA03 ORDER BY 1, 2;
 *** Query completed. 6 rows found. 2 columns returned.
 *** Total elapsed time was 1 second.
 *** Query completed. 6 rows found. 2 columns returned.
 *** Total elapsed time was 1 second.
          ID_N  C_TXT
--------------  -------------------------
            1.  A
            2.  B
            3.  C
            4.  D
            4.  E
            4.  F
 
HTH.
Cheers.
Carlos.