To suspend or unsuspend an account in WHM:
From Account Functions in the left-hand side menu click 'Suspend/Unsuspend an Account'
On this page you will see two boxes: one on the left containing a list of all currently hosted domains and one on the right containing a list of all the users for the hosted domains.
Choose the domain/user account that you wish to suspend or unsuspend
Note: if you are suspending an account enter the reason in the box underneath the Suspend and Unsuspend buttons.
When you're done with your modifications click the Suspend button
If you are unsuspending an account, click the Unsuspend button instead
You will be taken to a new page telling you that the account has been Suspended or Unsuspended, depending upon which option you selected.