PO_ACTIONS.CLOSE_PO not closing blanket Release

Hi,

Our business needs to close long pending POs, both standard and Blanket releases. I have designed a custom program that uses the

PO_ACTIONS.CLOSE_PO API. This works fine for Standard POs whereas when changed the parameters as shown below for closing Blanket Release the same is not working. Pls let me know where am going wrong or how i should go about. We are in R12.1.3.

  apps.fnd_client_info.set_org_context (p_org_id);

      fnd_global.apps_initialize (1174, 50871, 201);

     -- mo_global.init ('PO');

     

        mo_global.init (c_po_number_rec.potype);

        mo_global.set_policy_context ('S', p_org_id);