how do I change alternate "apple-ID". not alternate "email" address

If you mean the @me.com and possibly @mac.com versions of the primary @icloud.com address, these are all the same thing and you can't change any of them.

I know you think you are helping Roger, but you are simply incorrect. My apple ID, icloud.com and me.com addresses are all completely different so quit telling people they are the same. Its obvious you are unable to answer this question. So please stop trying.

People who had MobileMe and then moved to iCloud started with an @me.com address and then gained an @icloud.com address; older subscribers would have started as an @mac.com address. This would have been the ID/Login as well as the email address provided by the service.

If the text before the '@' is the same in all three cases then they are the same thing and cannot be changed. Messages to any of them go to the inbox . Of course you can set up additional addresses in the form of 'aliases'. Nowadays new ones can only be @icloud.com.

People who joined iCloud after MobileMe closed mostly have an ID which is a non-Apple address and of course an @icloud.com address but not (except for a very few cases) an @me.com address.

So when I said 'If you mean the @me.com and possibly @mac.com versions of the primary @icloud.com address, these are all the same thing and you can't change any of them.' then this is correct.

You may have a different set up because of the way you initially created your account.

And it is not your place to tell me what or what not to post.