To deactivate an existing account, click Browse Accounts in the left nav and select the account you want to deactivate (Figure 1):
Figure 1 Browse Accounts
Click the Deactivate button in the upper right of the user’s account and then click Deactivate Account to confirm the account deactivation.
Note: You can reactivate a user through the same process
Additionally, you can deactivate an account via an api as below: