Ah human factors
Personality is widely regarded as being cemented by the age of about seven. People's personalities do change but these are usually linked to severe incidents/ treatment such as a head injury or drug use.
What can be trained is behaviour . The subject is complex but behaviour depends on ones environment . Have a think about how you are in the flight deck or during an interview to how you are when with friends and family, you will probably be able to highlight differences.
Even in animals such as dogs we train behaviour not personality.
Hope that helps