You can use the Hosts page to edit the description for the target cluster host.
In the Web Interface toolbar, select the Platforms tab.
Select the platform, then click Edit.
Under Associations, select the Hosts tab, then click Edit (or double-click the cluster host) to open the Edit Cluster Host dialog.
Modify the Description for the Cluster Host resource.
Click Save to update the Cluster Host resource.
Click Close to exit the dialog.