On the resulting page, adjust your company address and click the Save button at either the top or bottom of the page.
This will change the main location of your account. If your account posts jobs to only one location, this will allow you to alter the location in which your jobs are posted.
If you or other hiring managers post jobs in multiple locations, you should adjust those addresses on each individual location. Adjust location addresses by navigating to Account > Manage Areas in the top right corner of your screen. On the left side of your screen, click the 'Locations' link. Here, you can edit each location by clicking the 'Edit' link to the right of the location name. If you need to add a new hiring location, click the Create New Location button. Learn more here: How do I add locations to my account?