public string change(string replaceString)
        {

            string finishedString = replaceString.Replace("Ä", "Ae").Replace("Ö", "Oe").Replace("Ü", "Ue");
            finishedString = finishedString.Replace("ä", "ae").Replace("ö", "oe").Replace("ü", "ue");

            return finishedString;
        }