Hi, Angelo,
When you create a new Google Sheets document it is given a unique key that will live with that document as long as it exists. This unique cannot be changed.
If you make a copy of an existing Google Sheets document the copy will get its own unique key and the same applies there as well.
The unique document key is within the document URL.
The unique document key is generated by Google's system and therefore cannot be changed. It works like this by design.
So the only way around this is to make a copy of the Google Sheets document in question. As describebed earlier, the copied Google Sheets document will have a new URL. Then you can delete the original document, or if you don't want to delete it then remove sharing to that document. Then send the URL from the copied document to the users. The copied document is then to be treated as the working document.
I also want to point out that though the document name is tied to the unique URL is has no affect on the unique URL if you rename the document. As I said earlier, the URL is assigned to the document by the Google system and remains with the document for life.
I hope that makes sense.
Ben Liebrand