It's probably too late now but you have a grace period of two hours after a listing starts (or relists) where you can change the duration to a longer one.
You can change the price any time except for the last few hours, so long as there are no bids on it.
You can revise the price down, I don't think you can put it up. You can't change from a BIN (buy it now) to an auction or vice versa. I am not sure about changing the time frame. I would suggest you try to "revise" your listing and it soon tells you if you attempt to change something that can't be changed. You do not have to go through with any changes you make when revising if you are not happy with your changes, it only relists with your new settings when you click the final "revise it" button at the end, so you can back out at any time prior to this and your original listing will not change.
You can revise the price down, I don't think you can put it up. You can't change from a BIN (buy it now) to an auction or vice versa. I am not sure about changing the time frame. I would suggest you try to "revise" your listing and it soon tells you if you attempt to change something that can't be changed. You do not have to go through with any changes you make when revising if you are not happy with your changes, it only relists with your new settings when you click the final "revise it" button at the end, so you can back out at any time prior to this and your original listing will not change.
More incorrect information. So long as you don't have bids on an auction you can change your price to whatever you want it to be.
