create table t_shipment (spp_id number, rfrl_strt_dt date);

begin
insert into t_shipment values (100, sysdate-356);
insert into t_shipment values (100, sysdate-350);
insert into t_shipment values (100, sysdate-200);
insert into t_shipment values (100, sysdate-100);
--
insert into t_shipment values (200, sysdate-356);
insert into t_shipment values (200, sysdate-150);
insert into t_shipment values (200, sysdate-100);
insert into t_shipment values (200, sysdate-2);
--
insert into t_shipment values (300, sysdate-1);
insert into t_shipment values (300, sysdate-10);
insert into t_shipment values (300, sysdate-15);
insert into t_shipment values (300, sysdate-20);
--
insert into t_shipment values (400, sysdate-2);
insert into t_shipment values (400, sysdate-6);
insert into t_shipment values (400, sysdate-4);
insert into t_shipment values (400, sysdate-3);
end;
/

commit;

SELECT spp_id, MAX (rfrl_strt_dt) rfrl_strt_dt
    FROM t_shipment
   WHERE spp_id IN (100, 200)
GROUP BY spp_id
--
UNION ALL
--
SELECT spp_id, rfrl_strt_dt FROM t_shipment WHERE spp_id NOT IN (100, 200);

SQL> select spp_id, case when spp_id in (100,200) then maxt else rfrl_strt_dt end as rfrl_strt_dt
  2  from (
  3  select spp_id, max(rfrl_strt_dt) over (partition by spp_id) as maxt,
  4         rfrl_strt_dt, row_number() over(partition by spp_id order by rfrl_strt_dt) as rn
  5  from t_shipment)
  6  where spp_id not in (100,200) or rn = 1;
 
    SPP_ID RFRL_STRT_DT
---------- ------------
       100 12/18/2016 1
       200 03/26/2017 1
       300 03/08/2017 1
       300 03/13/2017 1
       300 03/18/2017 1
       300 03/27/2017 1
       400 03/22/2017 1
       400 03/24/2017 1
       400 03/25/2017 1
       400 03/26/2017 1
 
10 rows selected

select  spp_id,
        case grouping(rfrl_strt_dt)
          when 0 then rfrl_strt_dt
          else max( rfrl_strt_dt)
        end rfrl_strt_dt
  from  t_shipment
  group by grouping sets((spp_id),(spp_id,rfrl_strt_dt,rowid))
  having grouping(rfrl_strt_dt) = case
                                    when spp_id in (100,200) then 1
                                    else 0
                                  end
/

    SPP_ID RFRL_STRT
---------- ---------
       100 18-DEC-16
       200 26-MAR-17
       300 08-MAR-17
       300 13-MAR-17
       300 18-MAR-17
       300 27-MAR-17
       400 22-MAR-17
       400 24-MAR-17
       400 25-MAR-17
       400 26-MAR-17

10 rows selected.

SQL> 

SCOTT@orcl_12.1.0.2.0> SELECT DISTINCT spp_id,
  2  	    CASE WHEN spp_id IN (100, 200)
  3  		 THEN MAX(rfrl_strt_dt) OVER (PARTITION BY spp_id)
  4  		 ELSE rfrl_strt_dt
  5  	    END rfrl_strt_dt
  6  FROM   t_shipment
  7  ORDER  BY 1, 2
  8  /

    SPP_ID RFRL_STRT_DT
---------- ---------------
       100 Sun 18-Dec-2016
       200 Sun 26-Mar-2017
       300 Wed 08-Mar-2017
       300 Mon 13-Mar-2017
       300 Sat 18-Mar-2017
       300 Mon 27-Mar-2017
       400 Wed 22-Mar-2017
       400 Fri 24-Mar-2017
       400 Sat 25-Mar-2017
       400 Sun 26-Mar-2017

10 rows selected.