permalinks’ automatically redirection trouble

Hi, everybody.

What I have done is: 1) Set the permalinks structure to use tag “%postname%” only. 2) I made a page with title “about” by using the Pages–Add new in the control panel. After that, the page can be viewed at “http://localhost/about”. 3)And then I changed the page’s title to “about me”, so the permalink of the page was changed to “about-me”, obviously at this moment the page can be viewed at “http://localhost/about-me”.

So, the trouble is:When I type “http://localhost/about” in the address bar, the url will automatically redirect to “http://localhost/about-me”.

What I wanna:Delete the old permalink “http://localhost/about”, when I visit the url, the wordpress will view it never existed, like content not found.

What should I do? Appreciating for your answers.