Here's how to change your Yahoo! password from within Yahoo! Messenger:
1. Click the Messenger menu and select My Account Info. The Sign in to Yahoo! window opens.
2. Enter your current password in the Password field and click Sign In. The Account Info page opens.
3. Click Change your password. The "Change your Yahoo! Password" window opens.
4. Enter your current password in the Enter your Current Password field.
5. Enter your new password in the Choose a New Password field.
6. In the Confirm your New Password field, confirm your new password by entering it again.
7. Click Save to put your new password into effect. You'll see a message that says you've successfully chosen a new password.
8. Click Continue. You'll be asked to review account sign-in settings. Make any updates to this information that you would like.
9. Click Continue again. You'll be returned to the Account Info page.
10. When you're done, be sure to click Finished.
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