Online chess

I don't know which Forum Category include Online Chess, so I will put this question just at Help & Support...

Whatever,

My problem is that I don't know what means "takeback".
You have 3 variations in online chess:

1. This is a rated game
2. This is an unrated game
3. This is a TAKEBACK game 

So, what does it mean (3.)?

Thanks for answer

You can ask your opponent if you can take back a move.

Is it rated? Or you can choose if it'll be unrated/rated?

It's always unrated.

OK, thanks for all answers!! :)

We shall have a go of it, what you think?

Herr Smith!

Tielz, of course. I try it with my brother and I think you can take back a move (if you already submitted) before opponent moves.