Select the first record of the last group when there are repeating groups

Question

Trying to select the first record of the latest repeating STATUS groups for each POLICY_ID. How can I do this?

Edit/Note: There can be more than two status repetitions as shown in the last three rows.

View of the data:

Desired output:

SQL for data:

--drop table mytable;
create table mytable (ROW_ID Number(5), POLICY_ID Number(5), 
                      CHANGE_NO Number(5), STATUS VARCHAR(50), CHANGE_DATE DATE);

insert into mytable values (  81, 1, 1, 'A', date '2018-01-01');
insert into mytable values (  95, 1, 2, 'A', date '2018-01-02');
insert into mytable values ( 100, 1, 3, 'B', date '2018-01-03');
insert into mytable values ( 150, 1, 4, 'C', date '2018-01-04');
insert into mytable values ( 165, 1, 5, 'A', date '2018-01-05');
insert into mytable values ( 175, 1, 6, 'A', date '2018-01-06');
insert into mytable values ( 599, 2, 1, 'S', date '2018-01-11');
insert into mytable values ( 602, 2, 2, 'S', date '2018-01-12');
insert into mytable values ( 611, 2, 3, 'S', date '2018-01-13');
insert into mytable values ( 629, 2, 4, 'T', date '2018-01-14');
insert into mytable values ( 720, 2, 5, 'U', date '2018-01-15');
insert into mytable values ( 790, 2, 6, 'S', date '2018-01-16');
insert into mytable values ( 812, 2, 7, 'S', date '2018-01-17');
insert into mytable values ( 825, 2, 8, 'S', date '2018-01-18');

select * from mytable;

Answer 1

Hmmm . . .

select t.*
from (select t.*,
             row_number() over (partition by policy_id order by change_date asc) as seqnum
      from t
      where not exists (select 1
                        from t t2
                        where t2.policy_id = t.policy_id and
                              t2.status <> t.status and
                              t2.change_date > t.change_date
                       )
     ) t
where seqnum = 1;

The inner subquery finds all rows where -- for a given policy number -- there is no later row with a different status. That defines the last group of records.

It then uses row_number() to enumerate the rows. These outer query selects the first row for each policy_number.