You want the character graphic to change when they exit the vehicle based on what class he is? Just create a variable and create a set of numbers that correspond to different classes. You'll need paper and a pen for this (or sticky notes work better). I'll give you an example:
Variable 0001: Character Graphic
When 1: Warrior
2: White Mage
3: Black Mage
Now, when you change classes, set the variable based on what class they changed to. In other words, if you're changing from a warrior to a white mage, set the variable to 2. Then, when exiting the vehicle, create a set of conditional branches like so:
Conditional Branch: Variable [0001: Character Graphic = 1]
Change Graphic: Warrior
Conditional Branch: Variable [0001: Character Graphic = 2]
Change Graphic: White Mage
Conditional Branch: Variable [0001: Character Graphic = 3]
Change Graphic: Black Mage
Keep in mind that this will only work if you're using events for the vehicles and class changing. If you're using a script for one or the other, you'll have to make a script request. You'd just need someone to tell you how to change a variable in the script.
~Guardian1239