Redmine

When restructuring our wiki, I've run into a problem.
If the name of the wikipage ever existed and changed later, I'm not able to reuse this name.

Example:
We had a wikipage called "BorgBackup".
I've renamed it to "use Borg to extract archive" and I wanted to put it under a wikipage called "BorgBackup" so I can list other guides underneath it.
But when I want to make a new wikipage called "BorgBackup", I get redirected to the page made previously.

Is there a way to fix this? Maybe remove old wiki names from the database?
It really makes restructuring the wiki impossible this way.