Update field "DLV_BLOCK" using BAPI_SALESORDER_CHANGE

Hi friends,

I am using BAPI_SALESORDER_CHANGE and BAPI_TRANSACTION_COMMIT  to remove delivery block from an Order.

We are updating the below parameters and then calling the bapi.

   st_header_change-dlv_block    = ' '.

   st_header_change_x-updateflag = 'U'.

   st_header_change_x-dlv_block  = 'X'.

  CALL FUNCTION 'BAPI_SALESORDER_CHANGE'

     EXPORTING

       salesdocument    = v_salesdocument

       order_header_in  = st_header_change

       order_header_inx = st_header_change_x

     TABLES

       return           = t_return.

   READ TABLE t_return WITH KEY type = 'E'.

   IF sy-subrc <> 0.

     CALL FUNCTION 'BAPI_TRANSACTION_COMMIT'

       EXPORTING

         wait = 'X'.

  ENDIF.

But it's still wrong...

The field keeps the same value.

Thanks in advance.

Willian.