First things first: sign into your Yahoo! Mail account. Then:

1. Click Options in the upper right of your Mail page and select Mail Options.
2. Under “Management”, choose Mail Addresses.
3. Click once on the account you want to edit. Then click Edit. (To delete an account, click Delete.)
4. Edit your settings. You’ll recognize all the same options you had when you set up the account.
5. When you're done, click Save Changes.

Note: For security reasons, your password will not appear. If you need to type a new password, just type it in the space provided.