Slacker subscriptions are not able to downgraded directly. If you currently have a Premium Subscription to Slacker Radio, and would like to downgrade to Plus, then the way you do this is to cancel your current Premium Radio Subscription. Once the subscription has run through the remaining portion of your Premium Radio subscription and ends, then you can purchase a new Plus subscription.
To cancel your Premium Subscription:
To purchase a new Plus Subscription:
Note: All custom stations and favorites are saved to your account. Nothing is removed from your account when the subscription ends, so you will not lose any of your music. You will not be able to use any subscription features until you purchase a new subscription though.