go to localbitcoins.com , you'll be surprised that your neighbor has more bitcoins than you have. 
I am more interested in the process of putting it onto an exchange. Do you have to give the exchange the blockchain address password at some point?
All you have to do is create an account and transfer the bitcoins the address generated. Then you can sell it for the market price. I recommend coinbase if you are in america.
Where does the offline passphrase play into this?