i Forgot My Recovery Key

There’s no “changing” it.

You simply generate a new key and it replaces any prior key(s).

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Are you SURE that you want to use a recovery key? It carries substantial risks of it’s own for anyone not fairly adept at maintaining backups and detailed disaster recovery plans.

See these Apple excerpts

When you generate a recovery key, you can't use account recovery. 

Using a recovery key is more secure, but it means that YOU’RE responsible for maintaining access to your trusted devices and your recovery key.

If you lose both of these items, you could be locked out of your account permanently. 

See this article:

How to generate a recovery key - Apple Support

If you are logged in or can log in with your password , you can go in settings and make a new one.

Check that your icloud pass word and key chain is on n i cloud drive