There is nothing one can really do to change the families they are born into. Apart from completely ignoring their existence, you can not get rid of them. Even then they will always be your family.
Not everyone is luck enough to win the family lotto. Believe me, I should know. While I was dealt a fantastic mother, my father, well lets just say it would not be an exaggeration to call him a clinical sociopath and pathological liar. Thankfully I had very little contact with him in my life.
It still doesn't change the fact though that your family is your family, for better or worse, and you are pretty much stuck with them until the end. All you can really do is limit contact with those you dislike, and play nice at family gatherings you can not avoid. It is the way most people I know cope with their families.
At that point though you are left with a void. Families are there for a reason. They are a support system. They are supposed to love you unconditionally. They are supposed to be there for you when you need them no matter what. That is what family is supposed to be.
In reality though more than likely your real family will judge you harder than anyone else, disapprove of your life and decisions, and abandon you when you need them most in the interest of 'your own good'. I speak somewhat from experience. In the end your family will let you down on fulfilling that family role. I suppose because we share DNA our expectations for what people should be are harsher, and when they do not fit the ideal mold that you so desperately tried to form them in, well, harsh things are said, and people behave badly.
There is though a comforting thought, that while you can not change the family you were born into, you can always make a new family of your own. Family of choice can be just as strong, if not stronger than blood ties. The people you choose to call brother, sister, child, or whatever is someone who knows you as you are. They never had expectations of who you would be. They get to meet the fully formed you, flaws and all, and love you for that. Sometimes they grow with you, watch you change and mature, but they didn't raise you so expectations are different.
I have this amazing family of choice. People who I happily call brother and sister that have no blood ties to me at all. People who have seen me at my worst, and seen me at my best. People who have held me while I cried, and sobbed on my shoulder. I have battled through hard work and hard times with them, and drank and laughed and danced in the rain with them. I would drop everything to help them, and do anything in my power to make them happy. I would defend them to the ends of the earth against great peril because nobody harms one of my people.
Don't get me wrong, I still have strong ties to my blood family (well some of them). These people though, the people I chose to call family, that I have no tie to but love, they seem more real than my real family. I have more trust in their acceptance, I have more faith in their love, and I feel a strong connection that I do with anyone else.
They are the balm to my soul, the light that warms my heart, the thing that comforts me in the night, and brings a smile to my weary eyes.
They are my clan, my family, my people.