how to change the report layout in runtime into excel or pdf

By using the fnd_request.add_layout

   IF p_output_type = 'PDF'

   THEN

      p_call_status1 :=

         fnd_request.add_layout ('ONT',

                                 'ONT_REV_REG_RPT',

                                 'en',

                                 'US',

                                 'PDF'

                                );

   ELSIF p_output_type = 'EXCEL'

   THEN

      p_call_status1 :=

         fnd_request.add_layout ('ONT',

                                 'ONT_REV_REG_RPT_EXL',

                                 'en',

                                 'US',

                                 'EXCEL'

                                );

   END IF;