change traveler research in sendalert page .

I need to change the logical used in Pages/NewsAlert/[login to view URL] page to research travelers. Actually we are searching for traveler who have same destination of the alert. This is right as default research when the page load. But then the user may need to search manually using form fields as filters also for traveler with different destination or older travels. The important thing is that we have to check that the user write chars at least in one form field. Otherwise he could get thousands of records or get a timeout of the page.