Can someone guide me to merge two accounts into a family account?

I have read this page:

Merge accounts | Knowledge Base: Knowledge and help | mailbox

However, I fear that I don’t understand it correctly. What I read is that the user that you will want to link to the created family account has to liberate the principal address. But, such action is blacklisting the address for 365 days if I am correct.

I must admit that when I joined mailbox.org I did not see we could split the bills. So we created 2 accounts. But I wanted to share one alias between us. However, I realize that it seems impossible outside family account.

However, I don’t know how to "merge" our two accounts. Both accounts have active subscription.

On the page I quoted, they say:

• Create a new alias and set it as the new primary address of your account.
• Then remove the previous primary alias — that is, the email address you now wish to use within the team or family account.

But, as I said before, removing the alias, will blacklist it for 365 days. Do I miss something here?