using System;

using System.Linq;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        string oldPaymentDtTmString = "2021-11-18T12:35:28+00:00";

        var oldPaymentDtTm = DateTime.Parse(oldPaymentDtTmString);

        var newPaymentDtTmString = oldPaymentDtTm.ToString("yyyy-MM-ddTHH:mm:ss") + "+00:00";

        Console.WriteLine(newPaymentDtTmString);

        string oldBkDateString = "2021-11-18T00:00:00";

        var oldBkDate = DateTime.Parse(oldBkDateString);

        var newBkDateString = oldBkDate.ToString("yyyy-MM-ddTHH:mm:ss") + "+00:00";

        Console.WriteLine(newBkDateString);

        string oldCreationDtTmString = "2021-11-18T12:35:42.006+00:00";

        var oldCreationDtTm = DateTime.Parse(oldCreationDtTmString);

        var newCreationDtTmString = oldCreationDtTm.ToString("yyyy-MM-ddTHH:mm:ss") + "+00:00";

        Console.WriteLine(newCreationDtTmString);

    }

}