call function 'BAPI_PO_CHANGE'DELIV_DATE日期无法更新到采购

PO_CHANGENUMBER = I_OUTDLY-EBELN.
PO_POHEADER-PO_NUMBER = I_OUTDLY-EBELN.
PO_POHEADER-COMP_CODE = I_OUTDLY-WERKS.
PO_POHEADERX-PO_NUMBER = 'X'.
PO_POHEADERX-COMP_CODE = 'X'.
W_GITEM_EKES-PO_ITEM = I_OUTDLY-EBELP.
W_GITEM_EKES-CONF_TYPE = 'AB'.
W_GITEM_EKES-DEL_DATCAT = '1'.
W_GITEM_EKES-CONF_SER = '0001'.
if P_SCHD = 'X'.
W_GITEM_EKES-DELIV_DATE = I_OUTDLY-EEIND.
W_GITEM_EKES-QUANTITY = I_OUTDLY-CONFQTY.
else.
W_GITEM_EKES-DELIV_DATE = I_OUTDLY-EEIND01.
W_GITEM_EKES-QUANTITY = I_OUTDLY-CFQTY01.
endif.
* W_GITEM_EKES-CONF_NAME = '订单确认'.
append W_GITEM_EKES to GITEM_EKES.
W_POCOND-CONDITION_NO = I_OUTDLY-EBELN.
W_POCOND-ITM_NUMBER = I_OUTDLY-EBELP.
W_POCOND-COND_UPDAT = 'X'.
W_POCOND-CHANGE_ID = 'U'.
W_POCONDX-CHANGE_ID = 'X'.
W_POCONDX-CONDITION_NO = I_OUTDLY-EBELN.
W_POCONDX-ITM_NUMBER = I_OUTDLY-EBELP.
W_POCONDX-COND_UPDAT = 'X'.
append W_POCOND to POCOND.
append W_POCONDX to POCONDX.
call function 'BAPI_PO_CHANGE'
exporting
PURCHASEORDER = PO_CHANGENUMBER
table
POCONFIRMATION = GITEM_EKES
RETURN = RETURN .
DELIV_DATE日期无法更新到采购订单中是哪里错了，请大神指点