portal/app/Models/PackingList.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Relations\MorphMany;
use Illuminate\Database\Eloquent\SoftDeletes;

class PackingList extends AbstractModel
{
    use SoftDeletes;

    protected $table = 'packing_lists';

    public function orderSteps(): morphMany
    {
        return $this->morphMany(Step::class, 'owner');
    }
}