DateTime Reversed

Declare @DT varchar(35) = '1:30:21 PM 3/29/2017';

Select Cast(Right(@DT, Len(@DT) - Charindex(' ', @DT, Charindex(' ', @DT) + 1)) +
    space(1) + LEft(@DT, Charindex(' ', @DT, Charindex(' ', @DT) + 1)) as datetime);