Beste Bianca, van de Hollandamerica.com-site:
On festive formal evenings, women usually wear cocktail dresses or gowns and men usually wear business suits or tuxedos. There are approximately two formal nights per week. (Gentlemen: Although business suits or tuxedos are suggested attire for formal evenings, they are certainly not required. You are welcome to wear a jacket and tie on formal nights.) Formalwear for ladies and gentlemen can be pre-ordered for your use for the duration of your cruise. Just call Cruise Line Formalwear at 800-551-5091 to reserve and it will be ready in your stateroom when you board.
Henri.