Here is how you can upgrade, downgrade or cancel your plan i.e. subscription:
Click on your profile icon on the top left corner of your screen.
A dropdown box will appear...
If you are on a Team plan go to "Team Settings" (note you must ensure you are accessing this through the Org Manager's account) / Yet if you are on an individual plan click on "Profile and preference"Next select "Billing"
Click "Open Billing Portal"
Click "Open"
Select "Update Plan"
Select the the plan you wish to upgrade or downgrade to. If you wish to cancel paying for your place please ensure you select "Free" Plan and select continue (see example screenshot for this use case below).
And that's it!