Values from from select form field not updating in laravel - laravel

Question

I have a form that with select items from another table. The items list just fine in form view. The problem I am encountering is that the other fields in the form updates just fine except the drop-down lists.
I have checked and confirmed that the fields are all include in the $fillable array in the model.
When i dd($myinputVariable), its showing values of all form inputs.
This my form.
{!! Form::model($member, [
'method' => 'PATCH','id'=>'member-regform',
'route' => ['members.update', $member->member_registration_number]
]) !!}
<div class="form-group">
{!! Form::label('constituency_id','Constituency') !!}
{!! Form::select('constituency_id',$constituencies,
array('require','class'=>'form-control'))!!}
</div>
<div class="form-group">
{!! Form::label('ward_id','Ward') !!}
{!! Form::select('ward_id',$wards,
array('require','class'=>'form-control'))!!}
</div>
<div class="form-group pull-right">
{!! Form::submit('Save Changes',
array('class'=>'btn btn-primary')) !!}
</div>
{!! Form::close() !!}
</div>
My controller
public function __construct()
{
$this->constituencies = Constituency::where('county_id',8)->pluck('const_name','id');
$this->wards = Ward::pluck('ward','id');
}
public function update(Request $request, $id)
{
//
$member = Member::where('member_registration_number',$id)->first();
$input = $request->all();
$member->fill($input)->save();
Session::flash('message', 'Member successfully updated!');
return redirect()->back();
}
My Model
protected $fillable = array('constituency_id','ward_id');
After selecting a different ward_id or constituency_id, the value does not change from the older one after update. This issue has troubled my head for hours. Kindly help.

Answer 1

The 3rd element should be the selected value and the options the 4th:
{!! Form::select('ward_id', $wards, null, ['require', 'class' => 'form-control']) !!}
LaravalCollective drop downs