How to delete the authorization

I changed my email address longer time ago and it wokred up to now. But today I could not authorize a new eBook reader since one was damaged. I could de-authorize the broken eBook reader.
I thought now it would be time to use my actual email address to create a new AdobeID.

But I cannot delete the actual authorization in Digital Editions using my old email address.

Even if it the same account, just with a new email Adress. Btw. the old email address is still usable.

How can I delete the actual authorization and use one with my actual email Address?

I already tried to change the email address in the actual Adobe account but this also did not work.