We just give model operator group when we model for SSO using Authentication service. Do you mean updating model user's access group ? Actual operator wont be persisted in PRPC in SSO case. All the custom attributes mapped in authentication service will be populated in pxRequestor data page upon login.
Thanks. No, I don't want to update the model operator itself. I want to add or remove Access Groups from the operator who is created from the AuthService activity. It seems, that this operator must not be updated.