如何使用easyadmin更改更改默认角色

I'm making an intranet with easyadmin in symfony and I wondered how to changed default role ?

In easy_admin.yaml :

     - { property: 'roles', type: 'choice', type_options: { multiple: true, choices: { 'ROLE_USER': 'ROLE_USER', 'ROLE_ADMIN': 'ROLE_ADMIN','ROLE_TEACHER':'ROLE_TEACHER' } } }

My code is working I can update with ROLE_ADMIN or ROLE_TEACHER but ROLE_USER is still here and I can't remove it. When I update to teacher I have ROLE_TEACHER, ROLE_USER. How to update role without have ROLE_USER ? Thank you