How to withdraw yourself from high school?

Well, dropping out of High School is a serious thing, but, I will give the way how to.

Form a reasonable argument. 
such as;
 “I am not being served by this educational system. I am not challenged, interested, or inspired by the curriculum or the educators. I am choosing to drop out of high school so that I can pursue higher education on my own and find an educational institution that fits my academic goals.”

You should also think about your future with this decision, as this will absolutely change your life.

Some states allow students to drop out at 16, while others will not allow you to make that decision until you're 18 (Check and see if you can)

Talk to your guidance counselor or administrative advisor about the required paperwork. Each state and school district has different forms that you and your parents need to fill out. Make sure to consult with the appropriate person at your school to find out which documents need to be filed and when they have to be returned.Be aware that your guidance counselor may try to talk you out of your decision. Be prepared to offer your reasons for making your decision and be confident in your decision.

Also, I'd recommend schooling yourself, such as a home school or online school program. Another good way is to get your GED

Hope this helps!

A. true, according to bjs