How do you change your security question on battlenet?

A blizz blue post said this:

Please note that the First Name, Last Name, Secret Question, and Secret Answer on an account cannot be changed. In addition, the account name itself cannot be changed or reset. It is not possible to "wipe" an account or to re-use an Authentication Key for any reason. Once the key is used once and the account is created, that is permanent.

Blizzard Technical Support

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