Give Minecraft Real Right?

I'm playing minecraft Java with a friend. And we got realm in order to be able to gamble together. But now we have the problem that he only has rights, because it's his world, and I would also like to have rights so that I can teleport etc., but he doesn't know how to give me rights. (./ op name) does not work

Does anyone know how to do that?

https://minecraft-de.gamepedia.com/...m/Operator