II Corinthians 5:17 makes it appear that Christians can change. It states: Therefore if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.
In the Old Testament Ezekiel gives us these word from chapter 36:25-27. I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols, I will cleans you. And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my spirite within you, and cause you to walk in my statutes and be careful to obey my rules.
True Christians can change, for God makes it all possible through a spiritual renewal.
The Bible In Your Hand 