Forum Moderators: phranque
Mod_rewrite does not change URLs.
You need to change the links on your pages to the new URL format.
Then you use mod_rewrite to connect requests for those URLs to the old internal filepath on the server using an internal rewrite.
Additionally, you also set up a redirect from the old URLs to the new URLs so that the old URLs cannot be indexed.
The sticky post at the top of the forum points to several previous threads where the process is described in detail.