Oracle 18c

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create table mytable (
	id int,
	"date" date,
	status varchar2(5)
);
begin
insert into mytable values(15643, date'2020-03-10', 'ON');
insert into mytable values(15643, date'2020-03-15', 'test');
insert into mytable values(15643, date'2020-03-20', 'OFF');
end;
/
1 rows affected

select 
    id,
    "date" from_date,
    case when status = 'ON' 
        then lead(case when status = 'OFF' then "date" end ignore nulls) 
            over(partition by id order by "date")
    end to_date,
    status
from mytable


ID
FROM_DATE
TO_DATE
STATUS


15643
10-MAR-20
20-MAR-20
ON

15643
15-MAR-20
null
test

15643
20-MAR-20
null
OFF


select 
    id,
    "date" from_date,
    case when status <> 'OFF' 
        then lead(case when status = 'OFF' then "date" end ignore nulls) 
            over(partition by id order by "date") - 1
    end to_date,
    status
from mytable


ID
FROM_DATE
TO_DATE
STATUS


15643
10-MAR-20
19-MAR-20
ON

15643
15-MAR-20
19-MAR-20
test

15643
20-MAR-20
null
OFF


select 
    id,
    "date" from_date,
    case when status <> 'OFF' 
        then lead(case when status = 'OFF' then "date" end ignore nulls) 
            over(partition by id order by "date") - 1
        else lead(case when status = 'ON' then "date" end ignore nulls) 
            over(partition by id order by "date") - 1
    end to_date,
    status
from mytable


ID
FROM_DATE
TO_DATE
STATUS


15643
10-MAR-20
19-MAR-20
ON

15643
15-MAR-20
19-MAR-20
test

15643
20-MAR-20
null
OFF

ID	FROM_DATE	TO_DATE	STATUS
15643	10-MAR-20	20-MAR-20	ON
15643	15-MAR-20	null	test
15643	20-MAR-20	null	OFF

ID	FROM_DATE	TO_DATE	STATUS
15643	10-MAR-20	19-MAR-20	ON
15643	15-MAR-20	19-MAR-20	test
15643	20-MAR-20	null	OFF