So let’s say you have http://originalurl and you want to change it to http://newurl. Don’t do it through IIS!!! Pretty much everything you will ever need to manage a Sharepoint farm will always be found in CA.
Here’s how you accomplish this simple task:
1. Login to CA
2. Click the Operations tab
3. Click on “Alternate Access Mappings” under Global Configuration
4. In the top right, the default view is “Show All”. Just choose the web application you want to change.
5. Click Edit Public URLs and change the URL to whatever you want it to.
Done! Test it out and verify it works.