You can de-activate a user on the Organization users page.
Users do not receive an email notification when their account is activated or de-activated.
- In the top-right corner of the page, click your account.
- Click Account settings.
- In the Your Organization section, click Users.
- In the row of the user you want to de-activate, click the Actions icon, and then click De-activate.
- Click Yes, de-activate user.