Yes, absolutely, you can make changes as an unregistered user.
You don’t need a password to make the update, you’ll see the final screen to confirm the update has two ‘sides’ (left and right), the RIGHT side is for unregistered users, just enter your email address, you’ll get an automated email asking you to click a link to confirm the change, and bingo, it will be live.
You’ll also notice a checkbox which you can uncheck or check to register yourself at the same time. Leave it checked to register your account (so you can make instant future updates), uncheck it if you prefer to stay unregistered. If you leave it checked you’ll also get an ACTIVATION email to activate your account so you can make future instant updates.
Notes on some terminology:
ACTIVATION = activating your user account
VERIFICATION = verifying a change or review if you are NOT a registered user