If you choose to let Google Chrome save website passwords, you'll see a prompt every time you sign in to a new website. If you click Never for this site in the prompt, your password for the site is not saved and the site is added to a list of password exceptions.
You can edit this list of exceptions:
Click the spanner icon on the browser toolbar.
Select Options (Preferences on Mac and Linux; Settings on Chrome OS).
Click the Personal Stuff tab.
Click Manage saved passwords.
In the Passwords dialogue that appears, scroll down to the "Exceptions" section at the bottom.
To remove a site from this list, select it and click the x that appears at the end of the row.
Now revisit the website and you should see the prompt to save your password information again, if you've allowed Google Chrome to show the prompt.
Mac Support