Sorry, I thought that you were inquiring about changes due to violence in a port.
for cruise line itinerary changes , you will just have to keep in contact with your cruise line. as we are all in the same boat.. lol
cruise lines change itineraries and even ships at the drop of the hat.. depending on local issues, be it war, crime, strikes, size of ship.
Like most cruisers here, we have experienced it all 
heck, we are off on a cruise in two weeks, and they changed the ship, ports have cancelled ( ship too big) or they just do not want cruise tourists any more.
Our itinerary has changed more than once, and we are still checking daily so that there are no unexpected surprises.
Unfortunately that is the way of cruising these days.
whatever changes you may encounter, I hope that you enjoy your cruise.
