Node.js + Socket.io + https?

I am writing game with Node.js by using socket.io for server side. Now i am writing code for normal http protocol but later i want to using https protocol. I have to change something to doing server with https? I think you know what I want to do!

No, everything is same. You only have to use https instead of http server like this:

var https = require('https');    

var options = {
    pfx: fs.readFileSync('./ssl/thekeystore.pfx')
}

var server = https.createServer(options,app);

server.listen(app.get('port'), function(){    
    console.log("Express server listening on port " + app.get('port'));
});

io = socketsio.listen(app);