Why not combine not updating the time in DOB with this?

IF UPDATE(DOB)

BEGIN

UPDATE P

SET DOB = dbo.fn_ReplaceTimeInDate(i.DOB)

FROM dbo.Patient P INNER JOIN

inserted i ON

P.PatientID = i.PatientID

where i.DOB <> cast(convert(varchar,i.DOB,112) as datetime)

SET @error_var = @@ERROR

--Error checking

IF @error_var > 0

GOTO rollback_tran

END