Change of Case from Upper to Lower

REPORT  ZRRSAMPLE.

PARAMETERS: p_str TYPE char100 .

DATA: string TYPE char100 .

INITIALIZATION .

  p_str = 'THIS IS THE TEST' .

START-OF-SELECTION .

  CALL FUNCTION 'STRING_UPPER_LOWER_CASE'
    EXPORTING
      delimiter = `_`
      string1   = p_str
    IMPORTING
      string    = string
    EXCEPTIONS
      not_valid = 1
      too_long  = 2
      too_small = 3
      OTHERS    = 4.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
    WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.


  WRITE:/ string .