Can I withdraw from one conference and attend another one with the same abstract? A few weeks ago I submitted a two-page abstract to a conference in environmental sciences/ecology/biology. I haven't received the decision yet – poster or presentation. A few days ago I found out there will be a different conference, where my contribution would fit better and the main speakers are directly from my field and I could finally meet them.

Due to funding I probably cannot attend both conferences, so I have to choose. Another approach would be to withdraw my current submission and send a different one to the second conference.

Is it unethical to withdraw my submission and send it to other conference?
It is not unethical, but people will not be pleased. 


usually conferences would like to have good presentations, and if yours is accepted, they would like to have it.
if it is currently under review, the reviewers put (sometimes significant) work in it. This work is wasted now.


Nonetheless, it happens that authors of accepted publications do not attend to a conference - which is much worse. So retracting it as early as possible wopuld be a good option.

If the work is under review, it might happen that the reviewers of the other conference overlap with your current reviewers. If I would be such a reviewer, I would immediately reject the second submission because I would assume the work was already published or it would be a duplicate submission (which in both cases would be unethical). 

You can avoid this situation by submitting something different to the second conference (or you can check the program committee for potential overlap - but it is not always visible who is serving as reviewers).