Princess Cruises, Carnival Cruise Lines and Holland America all announced major changes to their smoking policies. Smokers will soon be banned from lighting up in cabins on all the ships of all three lines. The Princess smoking ban, which also applies to cabin balconies, will become effective on all sailings departing after January 15.  Holland America said its ban on smoking in cabins, but not on balconies, would also take effect on January 15.  Carnival said its ban on smoking in all cabins would take effect December 1. The line will still allow both cigarette and cigar smoking on cabin balconies.  Also, Carnival said it was limiting smoking on its ships to dance clubs, designated areas within the casino and casino bar and certain sections on the open decks. All three lines said they were notifying those passengers already booked on cruises of their new policies. Officials said the moves reflect changing customer preferences.