I am teacher and my son had some issues a few years ago with 2 kids in his class teasing him. It escalated and I wrote an email to his teacher. She said I could request that he be placed in different classes from these other 2 kids the following year. It worked out well. Just email the teacher and ask if you need to write a letter to the principal or what the procedure is.
Agree, but I would CC the principal.
I taught in a school where the teachers actually placed the kids for the following year in classes. We did not put teachers' names on the lists, but divided the classes in a manner we felt was fair to all teachers. We split kids we felt should not be together, etc. Occasionally, we put some together that would be a good fit.
However, circumstances change over the summer. Enrollment may go down and a teacher slot may disappear. Sometimes when changes are made, the administrators may forget. It wouldn't hurt to send a reminder in late July.