SQL Server 2017

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CREATE TABLE tablename
    ([ID] int, [DATE] datetime, [RANGE] int, [STATUS] varchar(4))
;
    
INSERT INTO tablename
    ([ID], [DATE], [RANGE], [STATUS])
VALUES
    (123, '2019-09-30 00:00:00', 000, 'C'),
    (123, '2019-09-30 00:00:00', 001, NULL),
    (345, '2019-09-25 00:00:00', 000, 'C'),
    (345, '2019-09-30 00:00:00', 001, NULL),
    (567, '2019-09-30 00:00:00', 000, 'C'),
    (567, '2019-09-30 00:00:00', 001, NULL),
    (789, '2019-09-27 00:00:00', 000, 'C'),
    (789, '2019-09-30 00:00:00', 001, NULL)
;
8 rows affected

update t
set status = 'Y'
from tablename t inner join tablename tt
on t.id = tt.id and t.date = tt.date and t.status is null and tt.status is not null
2 rows affected

select * from tablename


ID
DATE
RANGE
STATUS


123
30/09/2019 00:00:00
0
C

123
30/09/2019 00:00:00
1
Y

345
25/09/2019 00:00:00
0
C

345
30/09/2019 00:00:00
1
null

567
30/09/2019 00:00:00
0
C

567
30/09/2019 00:00:00
1
Y

789
27/09/2019 00:00:00
0
C

789
30/09/2019 00:00:00
1
null

ID	DATE	RANGE	STATUS
123	30/09/2019 00:00:00	0	C
123	30/09/2019 00:00:00	1	Y
345	25/09/2019 00:00:00	0	C
345	30/09/2019 00:00:00	1	null
567	30/09/2019 00:00:00	0	C
567	30/09/2019 00:00:00	1	Y
789	27/09/2019 00:00:00	0	C
789	30/09/2019 00:00:00	1	null