getting parent relationship in form

Tab::make('config')
    ->label('Config')
    ->schema(function($record) {
        $parent = $record;
        return [
            FieldSet::make()
                ->relationship('detail')
                ->schema([
                    Select::make('sms_type_id')
                        ->options(SmsType::all()->pluck('name', 'id'))
                        ->afterStateUpdated(function (?string $state, ?Model $record) use ($parent) {
                            $record->sms_type_id = $state;
                            $record->location_id = $parent->id; <---need to set this parent ID relationship.
                            $record->save();
                        }),
                ])
        ];
    })