Is there a way to reset/change my Steam email without being logged on?

From the Steam Support Wiki, this is how you can change an email address from within Steam:

• Right-click on the Steam icon in the System Tray and select Settings or press the Settings button in the Steam menu. ('Preferences' for the Mac client).
• Press the Change contact email button.
• Enter your Steam Account password along with your new email and click Next.
• Check your new email and click the link sent to you by Steam Support. Do not close the Steam dialogue box while you retrieve the email. If you didn't receive this email message, please Contact Steam Support or try using a different email address.
• Return to Steam after you see the Success! page. The dialogue box in Steam should now confirm the email change. Please click Finish to complete the process.
• View your Settings in Steam and make sure the email is updated.

If you see an error message anytime during this process please Contact Steam Support with the error or try again later.

From: Changing the Contact Email for a Steam Account

If you cannot access the Steam client to follow these steps, then you will need to Contact Steam Support and explain your issue.

Sorry that cannont be accomplished because of the Family View blocking tactic used by the hackers. Steam doesn't seem to even know about it because you can't communicate with them without the pin.

Try using the Steam app. I did this and it’s way more helpful. It first asks for the password; like everything else say you forgot. It asks for email, then say you don’t have access. Then it asks for the card you used to purchase games and then that’s how I got my account back and then changed back my email.