Add n number of working days to date

Simply add the below FORM into you ABAP code and call it using the usual PERFORM command:
   DATA: ld_date TYPE sy-datum.
PERFORM calculate_date  using '-4'
  changing ld_date.

*&---------------------------------------------------------------------*
*&      Form  CALCULATE_DATE
*&---------------------------------------------------------------------*
*       Add/Subtract n number of months from a date
*----------------------------------------------------------------------*
*  -->  p_months  Number of months to add/subtract
*  <--  p_date    Start date and result date *----------------------------------------------------------------------*  FORM calculate_date USING p_months                  CHANGING p_date.  DATA: ld_datestor TYPE sy-datum.  ld_datestor = p_date.  CALL FUNCTION 'MONTH_PLUS_DETERMINE'  EXPORTING    MONTHS        = p_months    OLDDATE       = p_date  IMPORTING    NEWDATE       = p_date. ENDFORM.                    " CALCULATE_DATE