How do I change the phone number associated with my locked Apple Account to regain access?

To change the number you will need to have access to the account.

If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (get Apple’s own instructions in this article: What to expect during account recovery - Apple Support ) to regain access to your account. Account recovery might take a few days or longer, depending on the specific account information you can provide to verify your identity. One tip to using account recovery is to look for options in small blue letters beneath the normal log-in items if you cannot complete the requested information.

Here are links to posts by Community contributors which provide additional detail about the account recovery process and what to do if you do not receive a text or call: Activation Lockout Issues - Apple Community and How can I reset my Apple Account password? - Apple Community and How to delete Apple ID when you can't log… - Apple Community This thread outlines the multi-step process and final recovery —> My Apple ID is locked, how do I fix it? - Apple Community , and this one about things you should and should not do while waiting —> How can I recover my Apple ID after multi… - Apple Community This is a very long user contributed document about account recovery —> Apple Account Recovery: Complete Step-by-… - Apple Community