Combined Holiday and Chairman Appointment Party at a University

[Ruby]

Need help with invitation wording. My department has an annual holiday party each year for all employees which also includes many folks from other departments within a University and our outside business connections. We send around 900 invitations each year. This year we have a new Chairman of our department and we wanted to combine that "celebration" with our holiday party. We are not sure how to word the invitation. The party starts at 7:00, we plan to have some very brief remarks at 8:00 from some high ranking officials within the Univerity. It's an open buffet type of event with Chamber players for music. Not formal/black tie, more cocktail like but we don't usually say "cocktail party". HELP!