What parts of a person can change without any problems? can the mind change?

Yes: Aging changes all parts of a person, including the mind. Most of us live with those changes without major issues. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Drink enough water daily so that your urine is mostly colorless. Practice safe sex.

Depends on change: Many, if not all, parts of a person can change over time. A part that changes for the better is a change without problems. A part that changes for the worse is a change with problems. That's just how one can define a good or bad change. Change is inevitable, as they say. A person's job is to channel her energy into making things change for the better... whether it's in her mind or body or both.

Development: Development, both physical and emotional is occurring continuously (or so we hope!) Yes, the mind can change physically through the learning and aging process, as well as powerfully changing through the psychotherapeutic process.