To move to another plan, cancel renewal of your current subscription, wait for its paid access period to expire and then select an available new plan.
Cancel before the next renewal rather than waiting until the renewal date. Check the access-end date in your subscription details so you know when the current period finishes.
Review the new offer’s price and terms before purchasing. If you are unsure which plan is active or where it was bought, contact support first to avoid creating overlapping subscriptions.