Twilio TaskRouter: Need Help in Conference Call

I use task router enqueue and dequeue instructions to connect the caller to the worker. Everything is working perfectly fine. Now I want to add another agent in the same call. For that purpose, I need to convert that call into a conference. I am using Laravel. Here is I am enqueuing the call

$taskAttributes = [
        'channel' => 'voice', // Specify that it's a voice call
        'type' => $deptName,
        'departmentId' => $department_id,
    ];
    $enqueue->task(json_encode($taskAttributes),['timeout' => 60]);
    return response($response)->header('Content-Type', 'text/xml');

That is how I am dequeuing it

return response()->json([
            "instruction" => "dequeue",
            "status_callback_events" => "initiated,ringing,answered,completed",
            "record" => "record-from-answer",
            "status_callback_url" => url('ivr/statuseventCallback'),
        ]);

What I need is to convert the in progress call to conference so I can add another person to the same call.

I managed to do that. Sharing here for information.

When the Call is attended and in progress. I trigger an API to update the task

$task = $twilio->taskrouter->v1->workspaces($workspaceSid)
                            ->tasks($taskSid)->fetch()->toArray();

        $existing = json_decode($task['attributes'],true);
        $new = [
            "conference" => "redirect"
        ];
        $updated = array_merge($existing,$new);
        // dd($task['attributes']);
        $task = $twilio->taskrouter->v1->workspaces($workspaceSid)
                            ->tasks($taskSid)
                            ->update([
                                    "attributes" => json_encode($updated)
                                ]
                            );

Now every event in my webhook call will have this attribute in Task Detail. I am updating first the child leg of the call then the parent leg.

if(isset($taskAttributes['conference'])){
   $task = isset($postDate['TaskSid']) ? $postDate['TaskSid'] : '';
   $twilio = new Client($accountSid, $authToken);
   $twilio->calls($callData['call_sid'])->update([
      "method" => "POST",
       "url" => url('api/phone/addConf?tsid='.$task),
   ]);
   $twilio->calls($taskAttributes['call_sid'])->update([
       "method" => "POST",
       "url" => url('api/phone/addConf?tsid='.$task),
   ]);
} catch (Exception $e) {
  setErrorLogs('Twilio callIsNotUpdating'.$e->getMessage());
}             
exit;}

on this addconf just return the twiml conference.