Nested components

hello everbody,
i can’t pass variable value to child component from a form with select

       <select name="lavNum" wire:model="lavNum">

           <option value="lavNum">scegli</option>

            @foreach($lavanderie as $lav)

            <option value="{{$lav->id}}">{{$lav->ragione}}</option>

            @endforeach

        </select>

How to reflect value of $lavNum in the main component and child component?

Thanks
Massimiliano