This achievement is earned when you change careers for the first time. To make certain you earn this, when you get the chance to go to night school near the middle of the game, do so. After moving through the night school spaces, you will get the option to change careers or take a pay raise. Change careers and choose new one to earn this achievement.
There are also "bad" spaces you can land on where you will lose your job and be forced to choose another one. This will also unlock this achievement.