Change it 21 on a 45 day trial run at the Fremont. You get to exchange one card for a fresh one after a 50 percent match of the original bet. You can do it after splitting pairs, too, but only the drawn card can be replaced. The hand is then played as normal. Players may double and split after changing a card. A changed blackjack even gets paid as if it were dealt. Rules that offset the card exchange: 6 decks Dealer hits soft 17 Blackjack pays 6-5 No double down after splitting Surrender and re-split aces are not offered It looks to me like it's a way to get people to play 6:5.