gistfile1.cs

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string url = "http://localhost:15914/main.ashx?action=directorAddManager&name=%D0%9B%D0%B5%D1%85%D0%B0&status=true&pass=1234";
            
            Console.WriteLine(Uri.UnescapeDataString(url));
            //выдает http://localhost:15914/main.ashx?action=directorAddManager&name=Леха&status=true&pass=1234

            Console.WriteLine(Uri.EscapeDataString("Леха"));
            //выдает %D0%9B%D0%B5%D1%85%D0%B0

            Console.ReadLine();
        }
    }
}