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 organization name in the top right hand corner and select 'Team Members' from the menu that appears.
2) On the Settings page, click the 'Team Members' Tab.
3) Click on delete on the righthand side of the last sign in date.
4) Then it will prompt you asking if you want to delete the team member.
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.