Contact your instructor before submitting a paper that was previously submitted for a different assignment or purpose. If you would like to use the same paper, or papers with significant overlap, for different courses, explicit permission from the instructor of each course is necessary.
Reusing a paper is not always wrong. A paper you have already written may be very appropriate and speak to the topic assigned. The consideration is to avoid misleading the instructor. A student of academic integrity will communicate with the instructor to explain why a previously written paper is appropriate for the current assignment, and request permission to use it again. The student should be honest.
Graphic by Sara LeBlanc