You can update your MSN password at any time on the Microsoft Live website. If you've forgotten your password, you can reset it using the Live website as well. If you need to reset your password you must have access to either the email account or cell phone associated with your MSN account. If you have two-step verification in place, you must have access to both.
Log on to the MSN website, and ensure that you have access to your backup email address and cell phone -- if you have previously enabled two-step verification you will need both to log in. Click on the gear icon beside your profile near the top of the page and select "Settings." On the Settings page click the "Change account settings" button, then "Security & privacy," and finally the "Change password" link. Type your current password in the "Current password" field and the new password in both the "New password" and "Reenter password" fields, then click "Save" to confirm the change.
Click "Can't access your account?" on the Windows Live login page. Select "I forgot my password," then "Next." Enter the email address associated with your account, which is typically the one you used to create the account, then follow the instructions to type the characters displayed on the page and click "Next." MSN will ask you to choose how you prefer to receive a reset code, such as via a text message or email. When you receive the code, you can type it into the site to reset your password. You will need access to both your email account and your phone if two-step verification is enabled on your MSN account.