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Go to your wallet > Click on the drop down arrow where your steem dollars balance is > market

You should then be able to sell your steem dollars for steem and then transfer your steem out of there, steem dollars are just a peg to the dollar currency, they can be used in the steem store I think but I tend to just sell them for steem, not entirely sure why they're there to be honest but I hope the little tutorial helped.

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