How do you ask for a part-time job?
You'll want to have an in-person conversation with your manager about going part-time. A good option is to schedule a meeting and give your manager a heads-up about what you'd like to discuss. Being surprised with a big request may make your manager feel on guard, and cause them to respond poorly.
Why do you want to have a part-time job?
Part-time workers enjoy increased free time in which to pursue extracurricular activities. Not only can part-timers save on gas and car maintenance costs, but they may also be able to shave dollars from their monthly auto insurance premiums.