using System;

public class Program

{

    public static void Main()

    {

        var time = "04:05 pm";

        DateTime dateTime = DateTime.ParseExact(time, "hh:mm tt",

                                        System.Globalization.CultureInfo.InvariantCulture);

        Console.WriteLine(dateTime);

        // OR

        string Time = "16:23:01";

        DateTime date = DateTime.Parse(Time, System.Globalization.CultureInfo.CurrentCulture);

​

        Console.WriteLine(date.ToString("HH:mm:ss tt"));

        // OR

​

        DateTime dateNew = Convert.ToDateTime(time);

​

        Console.WriteLine(dateNew.ToString("HH:mm:ss tt"));

    }

}