Changing your course's list price will not change its referral link. After you change the price, it can take up to 24 hours for the system to update. The link will continue to redirect students to your course landing page. If you have opted into Udemy’s Deals Program, the referral link will automatically match the price Udemy is currently offering to that student for your course.
Coupon links work differently, once a coupon is created it cannot be edited, but you can deactivate the coupon and create a new one if you still have coupons available. All old, disabled coupon codes will automatically turn into referral links. This means that the student will see the lowest price available and the sale will be credited to you (97% revenue share). You can read this article for more information. 🙂