You can upgrade your account at any time by visiting the Plan and Usage page. You can also cancel auto-renewal of your Yesware account at any time from that same page by clicking the "Cancel Renewal" button towards the bottom of the page. If you cancel your plan, you will not be billed for any further charges from Yesware. Your account’s current features will be available until the end date of your current subscription. 

Since Yesware is subscription-based and you prepay for service, no refunds are provided for the unused remainder of your term when you cancel your account.