HOW to win friends and influence people? Easy. Prepare your case.
In business, you need to think through what should be done, why it is needed and also think how people might react. Only then can you decide how to make your case.
What is the proposal, the benefit, the cost? Why should change occur and do you have the best solution? How is change to be made?
Who is going to be affected and which people will be the most vociferous in their objections? When should the alterations be made?
Once you have this information, make your case, explaining the analysis that has been done, spelling out the benefits while revealing the costs.
As in most things, preparation is key.