I went to school with a boy named Elmer. That is, until he was about age 9 or 10, when his mother decided he should be called by his middle name, Edward.
Don't know why,as he was certainly never teased about it, it wasn't *that* unusual.
Anyway, the teacher complied, but we kids wouldn't adapt, and still addressed him as Elmer. Which he was fine with..he hadn't wanted to change, anyway. He liked his name.