You're always in control of your subscription.
Viewing your current plan
Go to Dashboard → Billing to see your current plan, billing date, and payment method.
Upgrading
Choose a higher plan to unlock more features. The price difference is prorated for the rest of your billing period.
Downgrading
Switch to a lower plan. Your current features stay active until the end of your billing period, then the new plan kicks in.
Cancelling
If you cancel, your shop stays active until the end of your paid period. After that, you'll be moved to the free plan. Your products and data are preserved.