frostyboy64,
I hate to say it, but it happened to me with the Carnival Jubilee. I had a dream itinerary for the southern Caribbean before I got my notice that the ship was being chartered. It would have been an opportunity to visit some of the other islands that the Carnival Destiny did not sail to. It was also just after I had booked my non-refundable airline tickets to Puerto Rico.
I was fuming.
Since then, because there are no laws protecting the cruiser if something like that happens, I have changed my mindset to only expect to board the ship and sail whereever she decides to go. I'm in it for the cruise experience rather then concentrating on ports. However, sometimes those changes by the cruise line can cause quite an expense.