using System.Globalization;
public static void Main()
var dateTimeUtc = DateTimeOffset.Parse("07/20/2023 20:29:45 -08:00");
var dateTime = DateTime.Parse("07/20/2023 20:29:45");
Console.WriteLine($"{dateTimeUtc.UtcDateTime}");
Console.WriteLine($"{dateTime.ToUniversalTime()}");