I'd like to understand how you can get a 404 searching these forums...
Anyway, to delete a page, you can (at least):
1) edit it and remove its content
2) delete the relevant file in the data dir (I guess you'll break some things, not sure, try to re-index after)
To rename/move a page, you can (at least)
1) edit the old to delete it (cut), and create the new one (copy)
2) rename the relevant file in the data dir (I guess you'll break some things, not sure, try to re-index after)
3) use
this plugin