If you are the creator of the space, you have the ability to remove team members from the space. This is accomplished by clicking “Members” under the Overview section on the right sidebar. When the Space Members page appears, hover over the team member you want to remove from the space. Click the X button to remove them. Click "Remove" to confirm the removal. This will delete the team member from the space and reassign their items according to these rules: http://support.kona.com/entries/21859602-what-happens-to-tasks-i-m-on-when-i-leave-a-space.
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