What is the difference between a receptionist and first impression?

Erm... A receptionist is the girl who works at the front desk of an office

A first impression is the impression that people get from you the first time they meet you.

Hope this helps
Why Every Company Needs a Director of First Impressions : Brazen Careerist - A Career Center for Generation Y (http://www.brazencareerist.com/2008/06/05/why-every-company-needs-a-director-of-first-impressions/)