This article shows how to re-submit an assignment and what happens upon re-submission. To learn more about how to submit work online, follow this link.
The student can resubmit an assignment any number of times until the submission deadline is reached. Each time the work is resubmitted, the previous submission will be replaced/overwritten with the newly-submitted copy of the assignment. Remember, each submission is time stamped so teachers will know when your work was turned in.
Upon uploading a new document, your resubmitted work will replace the earlier submission.