Each airport is served by comprehensive rail and road infrastructure, providing business travellers with a variety of options to enter London. All five airports offer direct rail travel into the heart of Central London, coach travel to the main Victoria terminus, and hire car, mini-bus, licensed black cab and taxi services by road. If you're a VIP business traveller, chauffeur services are also available, and with the exception of London City Airport, each also offer direct helicopter transfer into the heart of the city.
A travel professional would be able to help you determine if visas are required to travel to where you want to go. If they don't know for sure, they know where to send you for that information and get confirmation that you do or don't need one for the type of travel you are taking. For instance, for most cruises if you leave an U.S. port and return to the same U.S. port you probably don't need a visa to visit the ports. This is called a "closed loop" trip. But, again, most of the cruises. Always double check to see if one is needed.
Changes in Itinerary
When an airline ticket needs to get rescheduled or cancelled, chances are the airline or the online service provider will charge lofty fees. When booking with a corporate travel agent, most of the times schedule changes can be done at zero or minimal extra charges