Approving Access Role Request through custom logic

Hi Experts,

I am implementing the approval functionality in my custom program by calling standard methods UPDATE & SAVE.

These methods get called in standard Web Dynpro component GRAC_UIBB_ACCREQ_APPROVAL method APPROVE. Idea is to MIMIC the standard functionality in custom program.

It is not giving me any error but request status is not getting changed. I am also passing details to be updated in audit log through update method, but its not getting updated in the request audit log tab. 

   lo_session             = cl_grfn_api_session=>open_daily( ).

   lo_access_request_api ?= lo_session->get(

                                                   iv_object_id = l_reqid  ).

    lo_access_request_api->if_grac_api_access_request~update(

    is_request_data       = ls_req_data

    it_requser            = ls_request_data-requser

    it_reqlineitm         = ls_request_data-reqlineitm

    it_reqsys             = lt_reqsys

    it_audit_trail        = lt_audit_log ).

    lo_session->save( ).

Could anyone let me know if we can achieve the approval functionality by calling these standard methods in our custom code?

Thanks.

PK