You can update your PRO subscription anytime from your dashboard. You can change the billing period or cancel it. To update your subscription:
Go to Billing
Click on "Manage Subscription"
Change billing period from monthly to yearly and vice versa.
Your billing period will change after the active billing period expires. So if you change from monthly to yearly billing, you will be billed for one year ahead upon already paid month ending (and vice versa).
Cancel your Vsble PRO Subscription
Your subscription will immediately be canceled. Your account remains active until the already paid period reaches its end and will expire without renewal.