To delete members from your team, go to Team settings > Active Users tab. Open the context menu of a team member and choose Delete from team:
Delete team member
If the user is the owner of some boards/templates created in this team space you will be given a choice whether to pass the ownership to one of the team admins or delete them. Click the cross icon if you would like to change the owner-to-be.
Changing board ownership, while removing a user
The chosen user will lose all access to your team projects right away (without being notified). Please note that they will retain access to the team boards that were shared via a public link - if the user saved the links to these specific boards.
Removing members on the Team, Business plans
As an admin, you can add or remove team members at any point during your subscription period. After the removal of team members, you will see the notification that you now have vacant seats:
The message about seats released after removing users
Click Keep seat if you would like to invite other users to the vacant seats. Click Manage seats if you would like to decrease the team size. To reduce the number of seats, set a new team size and click Confirm.
To know more about the prorated system of charge, please check our article - Understanding Billing.