Error writing stream file

  

The stream was not writable

You receive this exception when you try to change a file that is in resource . Here is the code:

var assembly = Assembly.GetExecutingAssembly();
        Stream str = assembly.GetManifestResourceStream("PCCLC9875.versao.txt");

        String linha = "versao=" + INICIAL_VERSAO + ";revisao=00;compilacao=00";
        StreamWriter sw = new StreamWriter(str);
        sw.WriteLine(linha);
        sw.Close();
        str.Close();

I can only read, but when trying to change the error.