Problems with the Structure category

Hi,

In WordPress I had initially set “zugspitze” as a subcategory of “wanderregionen”. Then I decided afterwards that this should not be a subcategory after all, but a main category.

Correct is therefore https://berginstinct.de/thema/zugspitze/
The URL is also reachable, but unfortunately the old URL is still reachable now: https://berginstinct.de/thema/wanderregionen/zugspitze/

How can I remove the old URL? My structure looks like this: https://app.screencast.com/rWaFrtFVcbSnL`