Find the team which you'd like to modify/cancel a plan for and click on the team's name to open the side panel
The side panel will be revealed allowing you to click on Plans and then click Edit
Here, you'll be be able to add an end date for the team's plan. If you'd like to cancel the plan, click Cancel plan in the bottom left. If you'd like to make other modifications, instead click Next
Note: Only plans with 'Individual usage' will have a Next button.
On the next screen, you'll be able to add an end date to an individual team member (click No end date), toggle the slider next to an individual team member's name to change who can take advantage of the team's plan (this will remove their access immediately), review the monthly pricing of the team's plan, add/remove/modify the discount given to the team for their plan, or add access for a newly-added team member
When you've made your changes to the team's plan, click Update to save