this exchange system exists and is automatically proposed to some VIP status. Click on the VIP button at the top right of the site and find out your status. If you have the status to do so, then all you need to do is go to yourPrize Winnings" to have the opportunity to exchange all the Prizes you win.
why not exchange Prizes of less value or equivalent to the one won?? example: I win a prize to the Catch A Prize Silver and I prefer a prize from the Catch A Prize bronze, I exchange!!!! because I find the Prizes exchange system against madpoints not great!!! but that's just my opinion!!!!;-)