Yes! You may retake any of your courses when it's offered in a future session. Each offering of a course is assessed independently, and most MITx Online courses do repeat. Please note that payment for one session doesn't apply to a future session.
However, it's not possible to start fresh or reset your course progress in the same session.
Note: Un-enrolling from and re-enrolling in the same course session won't reset your course progress.