method IF_EX_ACC_DOCUMENT~CHANGE.
  DATA:
    ls_ext      TYPE bapiparex,
    ls_it       TYPE accit,
    lv_tabix    TYPE i.
  READ TABLE c_accit INTO ls_it INDEX 1.
  CHECK ls_it-blart = 'ZE'.

  READ TABLE c_extension2 INTO ls_ext INDEX 1.
  CHECK ls_ext-structure = 'ZFI_POSTING'.

  LOOP AT c_accit INTO ls_it WHERE blart = 'ZE'
                               AND prctr = space.
    lv_tabix = sy-tabix.
    READ TABLE c_extension2 INTO ls_ext
      WITH KEY structure  = 'ZFI_POSTING'
               valuepart1 = ls_it-posnr.
    ls_it-prctr      = ls_ext-valuepart2.
    ls_it-zuonr      = ls_ext-valuepart3.
    ls_it-sgtxt      = ls_ext-valuepart4.
    MODIFY c_accit FROM ls_it
      INDEX lv_tabix
      TRANSPORTING prctr
                   zuonr
                   sgtxt.
  ENDLOOP.
endmethod.