Mass Update Contact Layouts

Mass Update Contact Layouts

I have a couple of hundred contacts in Desk on an old layout. I want to move them to a new layout - ideally without having to manually edit 100's of contact records.

I tried exporting - in an attempt to set or change the layout on re-import (as this works in CRM) but there's no option to do so. 

I cannot seem to find a way to do it. Is there something I am missing?

Jan