In order for you to transfer your account to another device, you will first need to locate your Restore Code from a previous save.
Need help finding your restore code? You can find instructions here

Once you have your code ready, follow these steps to transfer your save:
  1. Install the game from the App Store or Google Play Store on the new device.
  2. On the new device press the “Enter Restore Code” button. You can find this button on the:
    1. Title screen
    1. Game settings menu
      1. Press the “Get Restore Code” button
      2. Tap “Already have a code?”
  3. Input your restore code and once you have confirmed that this is the appropriate account. Press “Switch Accounts”