Laravel hasMany detach

I am having an issue with Eloquent regarding removing child model: When this is executed in process2() I still have the deleted model which is not ok.

Model

    namespace App\Models;

    use Illuminate\Database\Eloquent\Model;

    class Model1 extends Model
    {
        public function seasons() {
            return $this->hasMany('App\Models\Seasons', 'series_id', 'id');
        }
    }

Service

class Process {
    public function process1($model1Instance) {

        for($model1Instance->seasons() as $season) {
            if(//whatever//) {
                $season->delete();
            }
        }
    }
    public function process2($model1Instance) {
        for($model1Instance->seasons() as $season) {
            //At this point I still have the deleted instance
        }
    }
}

Usage

$proc = new Process();
......
$proc->process1($model1Instance);
$proc->process2($model1Instance);

When process1() removes a model from the parent, how can I have it removed in process2()?

Is it ok if I just unset the model and reassign the array of objects(without the removed one) to Model1 like:

public function process1($model1Instance) {

for($model1Instance->seasons() as $season) {
    if(//whatever//) {
        $season->delete();
    } else {
    $childs[]=$season;
    }
}
$model1Instance->seasons = $childs

}

Tried:

$model1Instance->seasons()->detach($season);

but got: Call to undefined method Illuminate\Database\Query\Builder::detach()

via Chebli Mohamed