Different cocktail parties require different attire. A cocktail reception is usually a formal affair, which means women are expected to wear gowns, and men should wear tuxedos. If the event is a cocktail buffet, casual dress if often acceptable--men can wear slacks and a button-down shirt, and women can wear a skirt or slacks. A "traditional" cocktail party, where appetizers are served and guests are standing for most of the event, is usually semi-formal. For this occasion, it is best to wear a cocktail dress with heels--men can wear a sport coat and slacks, or a dark-colored suit. Guests should ask the host what the dress code will be to avoid looking inappropriate at the event, if the dress code is not indicated on the invitation.