If you install the Dehaze presets and they appear in Lightroom, but don’t have any effect on your photos, here’s what to do:

In Lightroom, go to Help → System Info, and make sure that you’re using Lightroom 2015.2 or 6.2, or later. If you have Lightroom 6.0 or 6.1, choose Help → Updates... to update to the latest version.
Make sure the photos you’re trying to use the presets on are using the latest Process Version. To update the Process Version of a photo, go to the Develop module and choose Settings → Update to Current Process (2012).