when you go to yor aution at the top of the page there is a button that says edit and the page comes up to edit your aution go to advanced option and add one day
I hope this helps, but when there are bids you can no longer edit your auctions and these eyeshadow are great . I use them and they do last all day :) If I didn't have them I would bid. So good luck to all the Bidders!