You can change your subscription at any time.
If you subscribed through Apple or Google
Subscription changes are managed directly by Apple or Google.
To change your subscription, go to your Apple or Google account settings and then to the Subscriptions section.
If you subscribed directly through May
Go to:
Settings > My Subscription
You will then be able to select the plan that best suits your needs.
What happens if I change my subscription during my current billing period?
When you switch from one subscription to another, the unused portion of your current subscription is automatically taken into account.
You will only be charged the difference corresponding to your new plan.