method if_ex_acc_document~change.
    data: wa_extension   type        bapiparex,
          ext_value(960) type        c,
          wa_accit       type        accit,
          l_ref          type ref to data.

    field-symbols: <l_struc> type any,
                   <l_field> type any.

    sort c_extension2 by structure.

    loop at c_extension2 into wa_extension.
      at new structure.
        create data l_ref type (wa_extension-structure).
        assign l_ref->* to <l_struc>.
      endat.
      concatenate wa_extension-valuepart1 wa_extension-valuepart2
                  wa_extension-valuepart3 wa_extension-valuepart4
             into ext_value.
      move ext_value to <l_struc>.
      assign component ‘POSNR‘ of structure <l_struc> to <l_field>.
      read table c_accit with key posnr = <l_field>
            into wa_accit.
      if sy-subrc is initial.
        move-corresponding <l_struc> to wa_accit.
        modify c_accit from wa_accit index sy-tabix.
      endif.
    endloop.
  endmethod.