Yes, you can change the price at any time on your publication's Settings page in the Payments section. Only new paid subscribers will pay the new rate once the price change has taken effect. Your existing subscribers will remain on the plan they originally paid for. If you'd like to request a change in price for your existing subscribers, visit the support widget and ask for a human support specialist.
Note: Subscriptions renew at the original rate the subscriber pays as long as they don't cancel and resubscribe.Â