How to programmatically close PO using PO_ACTIONS API

PO_ACTIONS.CLOSE_PO is the API used to programmatically close/final close Purchase Order. We have to pass P_ACTION parameter value as 'CLOSE'/'FINALLY CLOSE' depending on the requirement to close a Purchase Order
--Sample wrapper procedure  to close  purchase order
CREATE OR REPLACE xx_po_close_prc(p_header_id NUMBER)
IS

 lv_result BOOLEAN;
 lv_return_code VARCHAR2(20);
 lv_header_id NUMBER := p_header_id;

CURSOR c_po_details IS
SELECT
pha.po_header_id,
pha.org_id,
pha.segment1,
pha.agent_id,
pdt.document_subtype,
pdt.document_type_code,
pha.closed_code,
pha.closed_date
FROM apps.po_headers_all pha, apps.po_document_types_all pdt
WHERE pha.type_lookup_code = pdt.document_subtype
AND pha.org_id = pdt.org_id
AND authorization_status = 'APPROVED'
AND pha.closed_code <> 'FINALLY CLOSED'
AND pha.po_header_id = p_header_id; -- Enter the PO_HEADER_ID if one PO needs to be Closed/finally closed

BEGIN

-- Parameters :

  -- p_docid : Header ID for Document
  -- Table: PO_HEADERS_ALL.PO_HEADER_ID  
  -- p_doctyp : Document Type
  -- Table: PO_HEADERS_ALL.TYPE_LOOKUP_CODE
  -- Values : STANDARD, BLANKET, RELEASE
  -- p_lineid : Line ID for Document
  -- Table: PO_LINES_ALL.PO_LINE_ID
  -- p_shipid : Ship ID for Document
  -- Table: PO_LINE_LOCATIONS.LINE_LOCATION_ID
  -- p_action : Action to be performed
  -- Table: PO_ACTION_HISTORY.ACTION_CODE
  -- Values: 'CLOSE' -- Close for Receiving
  --         'INVOICE CLOSE'
  --         'FINALLY CLOSE'
  -- p_reason : Reason for Closing. This must be entered for Manual Closing

  -- p_calling_mode : Whether being invoked from 'PO', 'RCV' or 'AP'. This
  --                  determines which of the Closed States needs to be
  --                  checked (receiving, invoicing or both). This must be
  --                  entered for Auto Closing

  -- p_conc_flag : Whether invoked from a Concurrent Process. This must be
  --               entered for Manual Closing and is used by the Funds Checker

  -- p_return_code : Return Status of PO Closing

  -- p_auto_close : Whether to invoke Auto Closing or Manual Closing

  -- p_action_date is added to function close_po()

FOR po_details_rec IN c_po_details
LOOP
  BEGIN
  lv_result :=    PO_ACTIONS.CLOSE_PO(
          P_DOCID => po_details_rec.po_header_id,
          P_DOCTYP => 'PO',
          P_DOCSUBTYP => 'STANDARD', -- Can be STANDARD, BLANKET, RELEASE
          P_LINEID => NULL, -- If want to close Line
          P_SHIPID => NULL,-- If want to close Shipment
          P_ACTION => 'CLOSE',
          P_REASON => 'Close Purchase Order ',
          P_CALLING_MODE => po_details_rec.document_type_code,
          P_CONC_FLAG => 'N',
          P_RETURN_CODE => lv_return_code,
          P_AUTO_CLOSE => 'N',
          P_ACTION_DATE => sysdate,
          P_ORIGIN_DOC_ID => NULL );
    IF lv_result = TRUE THEN
      DBMS_OUTPUT.PUT_LINE('Successfully closed PO#'||po_details_rec.segment1);
    ELSE
      DBMS_OUTPUT.PUT_LINE('Cannot close PO#'||po_details_rec.segment1);
    END IF;
   END;
 END LOOP;
 EXCEPTION
   WHEN OTHERS THEN
     dbms_output.put_line(' Exception closing PO using PO_ACTIONS.CLOSE_PO'||SQLERRM);
END xx_po_close_prc;