A working career change definition is 'the movement of a person from one job group to another.'
Notice that it's not just from one job to another. Using this definition indicates that somebody actually changes the type of work they do altogether.
If somebody moves from being a salesman in one office to being a salesman in another office, or even got a promotion in the same office, they have simply changed job. If they change from being a salesman to being a teacher, or an internet infopreneur, or a massage therapist, then they have changed career.
This career change definition also suggests that a career change is a bigger shift than just a job change.
To change direction completely often means that people need to learn new skills and abilities. Which may be of concern if somebody has to go back to school and may not be earning as much money as they used to, for example. Not being willing to start at the bottom is a factor that often puts people off considering a change.
However, a career change can also be very exciting! It can be used as a time to begin to make your own decisions, to put your life back on track, and to begin to do that thing that you're passionate about.