Unfortunately, you can not change your My TYPO3 username. This is because your username plays a central role in all systems and subsystems used on My TYPO3. If you are dissatisfied with your username, you need to create a separate My TYPO3 account (and delete your other account if necessary).
Should you decide to delete your My TYPO3 account, please send us an email to firstname.lastname@example.org with the request to delete it. Please make sure to send the request from the email address registered with My TYPO3. Our team will then process your deletion request and remove all entries. Your former login will be blocked as soon as the deletion process starts and you will receive an email when the deletion is complete.
It is important to note that the deletion of a My TYPO3 account also deletes any links to shop orders, certifications, organizations, and TYPO3 Association memberships.