Yes, it is of course possible to either upgrade or downgrade your subscription.
We are currently working on a flow where you can do this yourself, but as of now please go ahead and send an email to Rasmus Hansen @ email@example.com. In the subject field, please write either upgrade or downgrade and your team/organization/individual name.
Something in the lines of: Upgrade Team x to an organization subscription.
For more information regarding the different subscriptions/packages, click here.