You can update your profile information, including your email address, account password from the Settings > Account Settings page.
To change your first/last name, update the appropriate field and then press Save.
To change your email address, press the Update email button, enter your updated email address, and press Next. You'll be sent a confirmation code to the updated email address. Then, to confirm your email, enter that confirmation code and press Save. If you don't confirm your email by entering a confirmation code, you may not be able to receive notifications correctly from PicoNext.
To reset your password, see the article Reset your password
To close your account, see the article Close your password