Your device gets stuck at rescue email and you want to change it. Here are some easy troubleshoot steps that will help you to change rescue email in your device.
First, go to the My Apple ID on appleid.apple.com, select the option “Manage your Apple ID”, and then sign in.
Now select “Password and Security” option available over the left side of the page. You might ask one more security question before your proceed. If you wish to view the list of three security questions, you will see the option to use rescue address.
Add your account; choose the email address and password, follow the instructions.