The comments posted by the users on knowledgebase articles at the Client Support Center appear in the Staff CP at: Staff CP > Home > Comments
The Staff members may approve or delete the comments or mark them as Spam. Staff members can select the articles and use Approve/Spam/Delete button accordingly.
The comments can also be configured to be approved automatically from: Admin CP > Settings > Security > Auto Approve Comments
The Staff members can delete the comments, provided the Team they belong to, has the required permissions. The permissions to delete the comments can be assigned to the Teams from: Admin CP > Staff > Manage Teams > "Select Team" > Permissions: Staff > Base > Comments