Change is Constant
It is said that change is constant, so as humans, we can not do away with change. It's either we are changing for the best or we are changing for the worst, it is always a matter of choice but one thing is certain, we continuously change until the day we breathe our last breath.
I would say change could be a result of our experiences, interactions, environment, and perspective of life from our lenses or the lenses of others we've come in contact with. Nobody sleeps and just wakes up and decides that he or she wants to change, something or someone might and always triggers the decision or call for change.
Many people tend to wonder what is the reason a certain person who was nice and there for them, all of sudden is harsh and does not care for them, I guess you need to be sure you did not do anything to have warranted their change. No sane person would just decide to change towards a person if they had no particular reason for that.
It's also important that as humans as we grow, we should learn to evolve, and change. We should always unlearn, learn, and relearn because the world is evolving and things are not going to remain the same. As humans, make efforts to change, especially when people close to you have pointed out your wrong character and it is going to affect your friendships and relationships.
Change is constant and if you at a point in time, realize that you need change, do well to make change because it is necessary. Make changes when necessary in your life, because the necessary change in life can help you get to the level of life that you never imagined. Change is a life necessity