Depends on what you want to exchange it for. When you want to exchange it for Steem you can do this on the internal market:
https://steemit.com/market

When you want to Exchange it for other Cryptos you could use:

https://blocktrades.us

You can move them to the Bitshares platform too. And then trade then there. Which is a bit more complex:

https://wallet.bitshares.org

There are other ways, but they are on centralized exchanges which I do not use myself.