Can people change? Yes, I believe so but if the change is not "true", then his/her old ways will always surface.
I believe that even if they quote Bible verses, praise God in every social network update and participate on all the religious activities but if the "change" is superficial, when you interact with them and try to "test the waters" with provoking questions or comments hell will break loose.
As the wise troll in movie Frozen said, the mind is easy to change but to change the heart is not.
