If you are using the Classic Standard Assignment experience and a student has submitted the incorrect paper to an assignment, the first option would be for them to resubmit the correct paper. The class instructor can update the assignment settings to allow resubmissions; the student will then be able to resubmit the correct paper and overwrite the previously submitted incorrect one as long as the assignment's due date and time have not yet passed.
If the student is trying to resubmit a paper after the assignment due date has passed, they will not be able to. Please note that this is intended behavior; resubmissions are not allowed once the assignment's due date and time have passed, even if the assignment allows for late submissions to be made. Late submissions are only available for first submissions.
The class instructor can also remove the incorrect paper from the assignment inbox and submit the correct one on behalf of the student. Or, if late submissions are allowed, let the student submit again.
If you are using the New Standard Assignment experience, resubmissions are automatically enabled so the student can resubmit if the due date has not passed. If the due date has passed, instructors can give students extensions on an individual basis. This means that they can give this specific student an extension on the due date, allowing them, or the instructor, to resubmit the correct paper. Further information on how you can do this can be found here.