How can you change the mind of people, when they have their mind set on one thing?

Its an Art to influence, negotiate and convince people; some people are gifted this talent and some needs to acquire.

The following method needs to be adopted when influencing tough cookies (quotes from Deepak Chopra):

1. Be sincere and truthful. Don't be manipulative.2. Appeal to what someone else already believes. Don't impose your own belief system.3. Be aware of the other person's blind spots. Don't assume they are open-minded.4. In general, persuade through reason, not emotion. Don't assume that emotions aren't in play, however.5. Make the other person feel right. Don't make them feel wrong (Offensive).

By you doing the right thing and let see the benfits

Why do you want to change the people mindset?  Are they your family members where you have no other option except convincing them with your rational / reason and estimated benefits.  If they are your colleagues and subordinates in office, you need to evaluate their strenth and weakness.  If they continue to resist you better change them instead of changing their mindset, because, one cannot continue spending money on futiles.  If you are social reformer, you have hard task in hand to change the mindset, because, you are going against the cultural genetics.