Use revoke role to revoke roles from users and other roles:
revoke role role_name [{, role_name}...]from grantee [{, grantee}...]
where:
role_name – is the role being revoked. You can specify any number of roles to be revoked.
grantee – is the name of the user or role. You can specify any number of grantees.
All roles listed in the revoke statement are revoked from all grantees.
You cannot revoke a role from a user while the user is logged in.
