I have tried to end auctions early many times, even without bids it will not let you after acertain amount of time. Unless there is another way besides checking listing and clicking on end auction.
I use Turbo, but I assume it uses the same rules. Requirements Your ability to end a listing early depends on the amount of time remaining in the listing and whether the listing has received any bids. Timing Number of bids Can the listing be ended early? Fee for ending a listing early 12 or more hours left in the listing No bids Yes No 1 or more bids and you want to sell to the high bidder Yes No 1 or more bids and you want to cancel bids Yes Yes Fewer than 12 hours left in the listing No bids, including no canceled bids Yes No No bids, because you’ve canceled them No No 1 or more bids Yes, but you must sell the item to the high bidder. No 1 or more bids, but the item's reserve price wasn't met http://pages.ebay.com/help/sell/end_early.html No No