Amazon 2-Step Verification
Log in to account from Amazon.com or Amazon.ca instead of the normal portal URL
Go to Your Account > Login & security
Click Edit next to Two-Step Verification
Find the phone # you want to change & click Change
Enter the new phone # & click next
Verification code will be sent to the new phone #; enter it & click next
The page goes back to the “Two-Step Verification (2SV) Settings page” – if it’s all correct, log out