Hey
There was a coin swap a long time ago. People converted Cinni to Stakecoin (STK). After the coin swap ended the remaining Stakecoin were all sent to a burn address. So no one can spend those. Since they were burned no more coinswaps could be made after the coin swap date ended.
If you still have Cinni you can sell it on Cryptsy. The only way to send Cinni to Cryptsy is to ask Cryptsy support if they can give you their node ip to add to your conf file so you can sync to them to send Cinni to their exchange to sell.
after that you can buy Stakecoin from someone with that btc or you can use that btc for whatever you like.