def change_email(new_email, old_email, options = {})
      data = options
      data[:email] = new_email
      data[:change_email] = old_email
      api_post(:email, data)
    end
def change_email(new_email, old_email, options = {})
      data = options
      data[:email] = new_email
      data[:change_email] = old_email
      api_post(:email, data)
    end
params:
   new_email, String
   old_email, String
   options, Hash mapping optional parameters
 returns:
   Hash of response data.

 change a user's email address.