Force ReCrawling

How can force a crawler to totally recrawl a webite, without deleting it form the search index?
Normaly, if the site did not change, it will never be recrawlt, right?
I want to update the lastModified values to the actual creation dates of the sites.

How can force a crawler to totally recrawl a webite, without deleting it form the search index?

Please disable the “Check Last Modified” checkbox.

Normaly, if the site did not change, it will never be recrawlt, right?

No, it depends on the “last modified” value of a page on the site.