Switch Apple ID

I'm wondering if there is a way to switch your Apple ID on you're iPhone if you have already set it up with a different apple id. I had to sign in with my old apple id which had 0 data on it to set up my phone. My old device broke out of nowhere and when I try to switch my Apple id it says that the email I entered is already in use by another Apple id. My guess is that I'm not signed out on the other device? therefore it won't let me in. But let me know