That is requested by your TA when booking. Call them and have them change it to table for two. That said, I have met some real interesting people on cruises. It might be worth the gamble. If you don't like the tablemates, talk to the maitre 'd at the end of your first meal. he will be happy to find you a new spot. And don't forget to tell your old table mates some friends asked you to eat with them. (You will be seeing them the whole week.