Partial too tight

[Hulk24]

How do i adust my partial so not too tight around my tooth ? I dont want go back to my dentist and have him do it. He is a real jerk. He complain each time have to make any adjustment to them.. In the picture, you will see red arrow pointing to part i want to adjust.. Please tell me the correct way how to do it. I know if you do it incorrect, you could break it. Thanks.