Follow these steps to delete a team member:
Note: In order to add team members, you will need to have account permission to edit your organization's team members.
1) Hover over your name in the top right hand corner and select 'Settings' from the menu that appears.
2) On the Settings page, click the 'Team Members' Tab.
3) Click the name of the Team Member you would like to delete.
4) Click the 'Delete Team Member' button on the actionbar.
You're all done!
Remember: Deleting a Team Member will remove them from your Organization and their permission settings will be forgotten. If you wish to have this person as a team member in future, you will need to add them again.