Every one of us hates the thought of changing. When our parents told us to be tidier, when our teachers told us to do homework, etc etc.... and remember you cannot change anyone. You need to provide a compelling case for them to change.
So instead of saying "CHANGE!" give them a "Choice". Choice is a word that is less threatening and it gives the person the power. When faced with a choice you are more willing to think objectively about it, and then accept the reason for change. To do this ensure that you don't confuse....provide a clarity around the choice, the clarity helps people to make a decision.
So start speaking by saying "We have some choices to make....."