hi is it possible to change vin in cas module ? if so . how ?

You can change CAS VIN from CAS Replacement.
Select CAS Replacement, then click on advanced button.

Can I change the model of the car? I have a working with minicooper cas, I changed chassis but it continues as mini has how to change it ???

In Autohex FA manager we restrict changing Tree items:
- Production year
- The engine type
- Model series
These 2 items will make a BIG difference when you change, 99.9999% you will be in a big mess after changing them.
In short: You cannot change the car model, because for sure you will be in a big problem.
The solution: Copy an FA from another car which is same model, engine, and year, after that you make the FA modifications.