Você pode usar um
UNION ALL
:select No, 'Flag_1' as FlagName, Flag_1 as Flag_Value
from yourtable
union all
select No, 'Flag_2' as FlagName, Flag_2 as Flag_Value
from yourtable
union all
select No, 'Flag_3' as FlagName, Flag_3 as Flag_Value
from yourtable
Ou um
UNPIVOT
:select no, FlagsName, flag_value
from yourtable
unpivot
(
flag_value
for FlagsName in (Flag_1, Flag_2, Flag_3)
) u