Knighthood is not just a title, it also means you are servant, subject to the monarch. My understanding is you have to become citizen for this. And while Brita

Knighthood is not just a title, it also means you are servant, subject to the monarch. My understanding is you have to become citizen for this. And while Britain allows dual citizenship, most countries do not. So in most cases you need to rescind your other citizenship in order to be come an actual knight.