Answer by iwhp for How to remove time portion of date in C# in DateTime object only?

Try this, if you use a DateTimeOffset, it will also take care of the timezone

date1 = date1.LocalDateTime.Date;

If you need to add hours, use this:

date1 = date1.LocalDateTime.Date;date1 = date1.AddHours(23).AddMinutes(59).AddSeconds(59);