Page urls appear to follow the following format:
https://yourinstitution.instructure.com/courses/14394/pages/entitled
Here entitled was the name I gave to the page so the url is formulaic with the page title appended.
I tried editing a page using the Canvas Live API which has an optional field for url - I kept the url the same as above, input entitled as the page title but changed entitled to newtitle in the url field
This did not change the url
but if I omit the title in the API the url is as I input it - but now the page title becomes the entire url...
So I think it's probably better to consider cahnging the title than trying to edit the url
Now if the page is in a module you'll also see something like ?module_item_id=938717 at the end of the url
I may have missed something but I don't think I could change the title if I submitted the module version of the url...
The difference between using the page url and the page url for the page within the module is that the latter displays buttons to access the previous and next items in the module
