The change will happen pretty slowly, but certain functions (ship scheduling and maintenance, supply, etc.) will get centralized over time. IF this merger happens (the shareholders of P&O Princess Cruises Plc. still have not approved it), I probably will seek another cruise line -- with Celebrity Cruises and Royal Caribbean International being the top two candidates. I also will be liquidating my shares of P&O Princess Cruises Plc. (LSE: POC) as soon as its opportune to do so if the shareholders vote to approve the proposed merger.
The unfortunate reality is that Carnival Corporation will represent about 75% of the combined company, and thus will have effective control. Carnival Corporation has an abysmal record of safety, including many recent incidents of major fires at sea, ships losing propulsion (which is a lot more dangerous than it sounds), and other serious incidents. That company's namesake line also amassed over five hundred complaints of sexual assaults on passengers by members of its crews in a five-year period -- an average of about two such incidents per week -- that apparently received little action from the company until the FBI launched an inquiry. Carnival Corporation also has an abysmal record of failure to respond in a reasonable fashion to legitimate complaints from passengers across all of the company's lines. I frankly do not want anything to do with a company that has so little regard for safety and for passenger satisfaction, either as an investor or as a passenger on any of the company's ships.
In a nutshell, I'm not cancelling the cruises that I have booked (through March) as it will take a while to implement the merger after shareholders approve it, but I also am not booking any new cruises with Princess unless and until shareholders reject the proposed merger.