AnswerFrom the GFI LanGuard console, one can set up rules to 'Acknowledge' or 'Ignore' vulnerabilities and patches. Once these rules have been set up, these patches would not be listed as missing in future scans. This is particularly useful for applications like new versions of Internet Explorer, .Net Framework, etc.
One can access the Rules Manager and review these rules by browsing to: Dashboard > Entire Network > Vulnerabilities > Rules Manager
In the Rules Manager, you'll be able to review the current rules and Remove expired rules or Remove the rule completely.
Once a modification has been made, the targets need to be scanned again for the changes will be visible.