I have submitted a messy manuscript to a conference due to the urgent deadline. After a period of revision, I corrected some mistakes and tidied the manuscript. Is it okay to send an email to the conference chair or somebody else asking to resubmit the manuscript? Or are there any other ways to resubmit?
I might have a slightly different take than @PsySp in his answer on this issue, but I think fundamentally we agree.
In my view, it's probably fair to email and ask the chair whether you can submit an updated version. But it's also fair for the chair to say no: like @PsySp says, deadlines exist for a reason and you can't assume that you're exempt from them. Get your house in order and build your paper in publishable form before the deadline comes up.
Deadlines exist for a reason. Asking for resubmission refutes the concept of deadline and gives you an unfair advantage over other submissions. If your article was not in a good shape you should consider make a stable version first and then submit it to the appropriate venue, not the other way around.
To answer your question: NO, do not ask the PC for resubmission. If your submission is messy, the most appropriate action is to retract your paper. This will save valuable time from the PC members and potential reviewers and will give you a good chance to work on the paper and submit it to an appropriate venue that would maximize your chances of a fair assessment.
Depends on how the submission system works and what your goal is. If it hasn't been long since the official deadline, there's a chance that the review process has not started yet, and the submission is still open. If you upload your manuscript via some website, you should just try and see if it allows you to upload a new version. I'm also sure nothing bad will happen if you ask the organizers if they would allow to submit a new version, again, assuming that you're just a few days late.
Now, if you're worried that your messy manuscript will be published somewhere, then you should not. In this case, you'll normally get a chance to prepare a new version.