Eloquent’s save() is not working

Following script will save nothing:

$member = MemberM::where('id', auth::id())
            ->select(
                "name",
                "email",
                "phone",
                "county",
                "district",
                "address",
                "verified", 
                'registered'
                )
            ->first();
$member->registered = 0;
$member->save();

Reason:

Because no primary column in select(), adding “id” column will save this problem.