Currently, you cannot change or reset your username.
However, you can re-register for a new account with a different username using the same email address.
Please follow the steps below to delete your current account and then create a new one.
Delete your current account
/shifter-support-documents/account/how-to-delete-shifter-account
Create a new account and set your desired username
/shifter-support-documents/quick-start/creating-shifter-account