If you have deleted or edited a coupon that was used for previous registrations, this will not affect your previous sign-ups. The current coupon settings will be applied to any new registrations.
If you are looking to edit a coupon that previous students have already used due to incorrect coupon settings, then any updates will need to be made in Stripe. For example, if you meant to create a coupon that only applied to the first payment in a subscription, but it is currently being applied to all payments, you can manually remove the coupon in your Stripe account.
For Thinkific Payments