You will be happy to know that most of them can be done through self-service!
To change the country associated with your Alpha Access application, you simply need to change the country associated with your account!
While you will not be able to modify the device you entered already, you can easily remove it from the list and add a new one.
This can be done by clicking on the right cross next to the name of the device you want to remove
Unfortunately, we don't offer this option as a self-service just yet. If you associated the wrong Steam account to your Pax Dei account, please contact our support for assistance!