Where to sell a wedding dress?

Ok so I bought a wedding dress online custom to my measurements. Well it was way too big! Took it to alterations and the only way to make it properly fit is to take out the lace back (the whole reason I bought the dress) anywho lol I decided to get a whole new dress. So now I need to sell the old one. Does anyone know of any websites or anything? Has anyone else had to do something similar? Results?