Can I connect the Nintendo account on the iPhone and iPad with Animal Crossing: Pocket Camp?

I would like to continue playing my current version of Animal Crossing: Pocket Camp on my iPhone, but since my Nintendo account is connected to the game on the iPad, the game says I'm already connected. Can't you connect two at the same time? And if not, how do I remove the account from the iPad without deleting data?

I think that's not possible. We tried that ourselves. We only made it from Nintendo to Nintendo. But I would like to teach you a better one. If you find a way, please let me know.

I deleted the game on iPad and iPhone, downloaded it on the iPhone and re-registered then it went and all data was still there.