Yes! In order to change your plan, just go to your Settings Page and under Plan & Payment, click Change Plan.
If you downgrade, or change from yearly to monthly billing, these changes will only take affect at your next scheduled renewal date.
If you want to upgrade or change from monthly to yearly billing, you can do this and you will be billed immediately for your new plan.
If you want to upgrade from one yearly plan to a higher one, please contact the support team.
You can find information here about how to pause your subscription here and what happens if you cancel your plan here.