If you need to disable a rule for a host, log into your UI and go to Administration > Rule Management > rules search
In this window, search for the rule that you would like to modify. Once the search resolves, click on the rule to open the modification window
Enter the name (not the IP) of the host you wish to change the rule for and set Disabled to <yes> and click <add>
You can verify the change by going to the top of the page and clicking on 'modified rules'. The newly changed rule should show in this window.