How Do You Change File Name Extensions

Hi All

Just a quick question, well I will try and make it quick.

I have a wordpress blog with page set up as

https://dachshund-tips.com/blog/3/click-here-for-a-review-of-the-top/
and
https://dachshund-tips.com/blog/4/click-here-for-a-review-of-the-top/

I am trying to change the file name /click-here-for-a-review-of-the-top/

Although they are diferent pages I need to change that part of the file
name. If somebody could tell me how to to do that I would really appreciate
it.

I have gone into the mange posts section and can edit the post I made
but cant work out where to edit the file name /click-here-for-a-review-of-the-top/

Thanks for your input

Stephen