I wanted to switch sizes but my size was not available anymore. I was like okay, I will go for another color then, until I saw I had to pay a lot extra (around 20€, but some up to 40!), I think because they were originally on sale... So in the end I just kept the original pair, even though they're a little bit too big. It seems not really fair to ask extra money to switch a size if your policy states that this is free... If that principle changes during a sale, you should tell the customers...