For actors and models, the poses would change to help portray the different characters you can play. However, I still look at your personality and your physical attributes. For example, if you can dance and have an elegant stance, those physical attributes can help portray a character.
During a session, I like to start with your natural stance. I then help coach you into a pose. This applies for everyone, even models. With models, we can start with some of your modeling poses to help portray a character we may be creating for a concept, but you can't see how you look in the camera. You know the angles of your body, but there may be slight tweaks, like a hand slightly out of place.
So a session for everyone would be a give and take. You start in a comfortable, natural pose, and then we work together through communication to bring out the best pose and expression for your images.