using System;

​

public class Program

{

    public static void Main()

    {

        // Your original input

        var dto1 = DateTimeOffset.Parse("2019-11-13T22:00:00.0000000+02:00");

​

        // Here's one way to get the value you asked for:

        var dto2 = new DateTimeOffset(dto1.DateTime, TimeSpan.Zero);

​

        // Here's another way, which does the same thing:

        var dto3 = dto1.Add(dto1.Offset).ToUniversalTime();

​

        // But note that dto2 and dto3 are a different point in time.

        // The actual UTC point in time is given by:

        var dto4 = dto1.ToUniversalTime();

​

        Console.WriteLine(dto1.ToString("o")); // "2019-11-13T22:00:00.0000000+02:00"

        Console.WriteLine(dto2.ToString("o")); // "2019-11-13T22:00:00.0000000+00:00"

        Console.WriteLine(dto3.ToString("o")); // "2019-11-13T22:00:00.0000000+00:00"

        Console.WriteLine(dto4.ToString("o")); // "2019-11-13T20:00:00.0000000+00:00"

    }

}