Hi roscius,
thank your for your answer.
What I forgot to say is that the folder I want to put the page in already exists. There are other pages already in this folder. Their permalinks look like they shoud, e.g.
ourwebsite.com/folder/page2
ourwebsite.com/folder/page3
…
So I want to add the current page to this “folder”.
And when I, just for trying, try to change the permalinks of page2 or page3, the “folder” cannot be changed, just the filename can be…
Best regards
Tom