Bringing finish time forward.

Yes, you can edit your auction to do that as long as there are no bids and as long as it's not due to finish inside 6 hours. Just go to the edit auction option on the listing and final tab shows you scheduled end times to edit.

Thanks Gary. Unfortunately I have 1 bid so original time will have to stand.

If the reason you want to bring it forward is that the bidder asked, then you could offer to remove their bid and add a Buy Now for them which means you could also edit the time. If it's for your own reasons, then best to leave it.