It depends on the school. BIL was sent to a bigger school for year 5 & 6, to prepare him for the size of high school (primary school only being 12 kids!)
He chose one school, but they said no because they already had too many kids in that grade. The second school was slightly smaller, so they accepted him happily.

A friend of mine just changed her DD's school. She had to pretend the father wanted to spend more time with her & so wanted her at school closer to him.