Change can only happen when the respective party is aware of the need to do so. Until that happens, try as you might to convince or even influence the person to change, only to realise that it was an effort best served elsewhere. When someone becomes aware to the need to change, it will then be a journey for the person to come to terms to finally take the steps to change. Understand that each one will have their own set of duration for it to bear fruit and that allowing enough time is essential. That is if you want a real effective change. But remember that before it can happen, you need to be aware of the need to change. It does not matter who said it or how many times it have been said to you, only when you are aware and have made the decision to change, will you be able to do so. That said, you might not be able to change a person, but you can definitely bring awareness into his or her life. If he or she decides to not be aware of it even after that, you should not waste your precious time and move on.