using System;

using System.Linq;

public class Program

{

    const string DateTimeFormat = "dd/MM/yyyy HH:mm";

    public static void Main()

    {

        //Console.WriteLine(string.Join(Environment.NewLine,  TimeZoneInfo.GetSystemTimeZones().Select(x=>x.Id)));

        var baseTime = DateTime.ParseExact("22/02/2019 10:00", DateTimeFormat, System.Globalization.CultureInfo.InvariantCulture).ToUniversalTime();

        Console.WriteLine("UTC: " + baseTime.ToString(DateTimeFormat));

        var datePST = TimeZoneInfo.ConvertTime(baseTime, TimeZoneInfo.FindSystemTimeZoneById("SA Pacific Standard Time"));

        Console.WriteLine("PST: " + datePST.ToString(DateTimeFormat));

        var dateEST = TimeZoneInfo.ConvertTime(baseTime, TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time"));

        Console.WriteLine("EST: " + dateEST.ToString(DateTimeFormat));

        Console.WriteLine("");

        Console.WriteLine("");

        Console.WriteLine("UTC: " + baseTime.AddMonths(-5).ToString(DateTimeFormat));

        var date2PST = TimeZoneInfo.ConvertTime(baseTime.AddMonths(-5), TimeZoneInfo.FindSystemTimeZoneById("SA Pacific Standard Time"));

        Console.WriteLine("PST: " + date2PST.ToString(DateTimeFormat));

        var date2EST = TimeZoneInfo.ConvertTime(baseTime.AddMonths(-5), TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time"));

        Console.WriteLine("EST: " + date2EST.ToString(DateTimeFormat));

    }

}