For Episode author profiles (Mobile Creator, Writer's Portal), you will need to create a new profile with the new email, which will not transfer your self-written stories. It is not currently possible to change the email associated with a Writer's Portal author account. 

The easiest way to transfer your self-written stories would be to copy your donacode manually into a new story on your new author profile. This will require recreating your characters, but you should be able to simply copy and paste the donacode text into the chapters in your new story on your new author profile using a PC or Laptop computer.