Step 1:
To change your subscription go to the Account Page and click billing portal.
Note: if this does not appear, please lodge a ticket at headquarter.io/support
Step 2:
Select the subscription you want, then click subscribe. If you are upgrading this will take you to the Stripe portal to complete your transaction.
Note: If you are downgrading your subscription, you will remain on your current payment level until the end of the billing period.