You will need to stop your current Silhouette Design Store subscription in order to downgrade to a lesser subscription level. Once your subscription is ended, you can subscribe anew to a lower-level subscription level.
Please rest assured that any current subscription credits you have on your account will be carried over to your new lower-level subscription from your previous subscription with their original expiration dates.
NOTE: Cancellation of a subscription paid with an annual charge, rather than monthly, may incur a cancellation charge if canceled before an initial three-month subscription period. See 'Canceling a Subscription' under the site's Terms of Use.