Most of us try to change on our own. Sit quietly, get to know yourself better, work at it. The course this comes from says that works.
It is also hard work. What makes it lighter, it suggests, is turning your mind toward a source of goodness beyond you: steady, generous, wanting nothing back. The course calls it the Supreme, or God. Plenty of people flinch at that word, usually because of what came attached to it: judgement, rules, a figure to fear. One of its teachers felt exactly that, and found a way through by separating the experience from religion.
You don't have to believe anything to try it. The teaching is plain that quiet attention to who you are already changes how you meet people. The upward connection is offered as an experiment, not a creed. You decide what it's worth after you've tried it.