possible to undo transaction without confirmations?

[ehmdjii]

hello,
is it possible to undo a transaction as long as it does not have any confirmations?
if yes, how?
thanks!

[Gabi]

Usually an unconfirmed transaction for more than a day disappear from the memory pool of the clients, but there is nothing you can do about that, just wait.

[Stephen Gornick]

is it possible to undo a transaction as long as it does not have any confirmations?
if yes, how?

You can't "undo" but you can create a competing transaction and try to get that mined first.

Most nodes will not relay a double spend so you'ld need to somehow get the transaction sent directly to a miner who would include that double spend instead of the original transaction.

But even then it becomes a race.  If the transaction has a good chance of being mined in the next couple of blocks your miner partner would need tens of TH/s of mining capacity to have a 50% chance or more of being able to mine the double spend.  That gets very expensive to do.  :-)

[CIYAM]

Unfortunately as of now there is not much you can do (apart from attempt a double-spend which I have found from personal experience is *extremely* difficult to do).

You'll probably find that in a day it will have been processed and until there is a way to *add a fee* to an existing tx the lesson is to *include* a fee if you want your tx to be mined in a reasonable amount of time.