Looks like you're thinking of getting a yearly subscription 🙂 And that's great — you can get the most out of Premium for a whole year at a significantly discounted price.
Web purchases:
To change your Premium plan, please reach out to our support team at support@verv.com and we'll check on our end if your subscription plan can be changed.
Google Play subscriptions:
1. Cancel the ongoing subscription in your Google Play Settings.
2. Once the monthly period has expired, use the in-app banners to re-subscribe.
Remember that Google Play does not divide the total amount charged for your subscription and charges one lump sum instead.