using System;

public class Program

{

    public static void Main()

    {

        DateTimeOffset? myDateOffset = null;

        var myDate = Convert(myDateOffset);

        Console.WriteLine($"Resultado: {myDate}");

    }

    private static DateTime? Convert(DateTimeOffset? myDateOffset)

    {

        if(myDateOffset.HasValue)

            return myDateOffset.Value.DateTime;

        return null;

    }

}