To Suspend or Un-Suspend a user do the following:
First click on the magnifying glass next to the user you want to manage. This will bring up the manage window.
Next you will click the Status icon. This will open the window to suspend a user.
Place a check in the Confirm change to suspended status in order to suspend this user. Then click the OK button.
If the user is currently suspended and you want to un-suspend them the window will look like this.
To un-suspend the user place a check in Confirm change to active status. Then click the OK button.
When a user is suspended the user account looks different on the user list page. Here is an example of what you will see after suspending a user.
The users icon will be gray and this user will not have access to your site.