...
Promo codes cannot be modified once they are in use, with the exception of the End Date which can be extended. Promo codes cannot be deleted once they are in use.
Promo Code Application
Promo codes discounts are applied last, after any other discounts that are applicable to an account-service are applied
A Promo Code can only be added to an account-service prior to billing. Once an account-service has been billed, promo code discounts cannot be applied to it
Multiple promo codes can apply to a service, but a single promo code can only apply once to the same service (no duplicates)
Prerequisites
Promo codes can be setup in the system immediately, there are no prerequisite configuration steps.
...