DATA :
 lv_char10 TYPE char10,
 lv_vbeln TYPE vbeln,
 ls_vbak TYPE vbak.

lv_char10 = '300841'.

lv_vbeln = lv_char10.
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
 EXPORTING
   INPUT = lv_vbeln
 IMPORTING
   OUTPUT = lv_vbeln.

SELECT SINGLE * FROM VBAK INTO ls_vbak WHERE vbeln = lv_vbeln.
IF sy-subrc = 0.
  WRITE 'SUCCESS'.
ELSE.
  WRITE 'FAIL'.
ENDIF.

Serkan AKKAVAK
Computer Engineer
serkurumsal@yandex.com