If you do something to get expelled from school then you will be banned from those school grounds and cannot go back to the school you were expelled from.
Being expelled doesn't mean you don't have to go to school anymore though so you will need to go to another school district or another school to attend.
If you get expelled you need to either do home school or enroll into another school that will accept you.
So no you cannot go back to the school you were expelled from but you can go to another school in another town, county, state etc.
So if your kid gets expelled then sometimes you may have to move to a different town or state to enroll your kid into another school or do home schooling for them.