In the start date box, type the date that you want this document demotion to appear in the search results. In the end date ...

In the start date box, type the date that you want this document demotion to appear in the search results. 

In the end date box, type the date that you want this document demotion to no longer appear in the search results.

Leave blank if the document demotion should take effect immediately with no expiry.