run workflow from backend

 CREATE PROCEDURE xx_activity (

   errbuf            IN OUT NOCOPY   VARCHAR2,
   errcode           IN OUT NOCOPY   INTEGER,
   p_itemtype        IN              VARCHAR2,
   p_activity_name   IN              VARCHAR2
)
AS
   v_errorname      VARCHAR2 (30);
   v_errormsg       VARCHAR2 (2000);
   v_errorstack     VARCHAR2 (32000);
   invalid_action   EXCEPTION;
   PRAGMA EXCEPTION_INIT (invalid_action, -20002);

   CURSOR c1
   IS
      SELECT item_key
        FROM wf_item_activity_statuses
       WHERE item_type = p_itemtype
         AND activity_status = 'NOTIFIED'
         AND process_activity IN (
                SELECT MAX (instance_id)
                  FROM wf_process_activities
                 WHERE activity_item_type = p_itemtype
                   AND activity_name = p_activity_name);
--AND item_key = 1228692;
BEGIN
   FOR c1_rec IN c1
   LOOP
      BEGIN
         fnd_file.put_line (fnd_file.output,
                            'EXECUTING FOR ITEM-KEY: ' || c1_rec.item_key
                           );
         wf_engine.completeactivity (itemtype      => p_itemtype,
                                     itemkey       => c1_rec.item_key,
                                     activity      => p_activity_name,
                                     --'xx_INSUFF_RESPON_BLOCK',
                                     RESULT        => wf_engine.eng_null
                                    );
         COMMIT;
      EXCEPTION
         WHEN invalid_action
         THEN
            wf_core.get_error (v_errorname, v_errormsg, v_errorstack);
            fnd_file.put_line (fnd_file.LOG, 'ITEM-KEY: ' || c1_rec.item_key);
            fnd_file.put_line (fnd_file.LOG, 'ERROR NAME: ' || v_errorname);
            fnd_file.put_line (fnd_file.LOG, 'ERROR MESSAGE: ' || v_errormsg);
            fnd_file.put_line (fnd_file.LOG, 'ERROR STACK: ' || v_errorstack);
      END;
   END LOOP;
END xx_activity;