using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        var original = @"http://PAC-KRYPTIQ-03/Documents\E\2017\E\05\E\R\E\A\E\RAMIREZ_MICHELLE_V_1971-10-26_2017-05-02_4077CA664412477B80FA82B6C2D37DFF.d1.pdf ";

        var shouldBe = @"http://PAC-KRYPTIQ-03/Documents/2017/05/R/A/RAMIREZ_MICHELLE_V_1971-10-26_2017-05-02_4077CA664412477B80FA82B6C2D37DFF.d1.pdf";

        Console.WriteLine(DecodeMessage(original));

        Console.WriteLine(shouldBe);

    }

    public static string DecodeMessage(string messageBody)

    {

        var searchAndReplaceDict = new Dictionary<string, string>

        {

            {@"\E\", @"\"    },

            {@"\", @"/"    }

        };

        foreach (var pair in searchAndReplaceDict)

            messageBody = messageBody.Replace(pair.Key, pair.Value);

        return messageBody;

    }

}