dialogflow update intent training phrases using php client library - php

Question

I am using dialogflow php client library for accessing v2 rest api of dialogflow. I can call detectIntent and other stuffs and it is working. But some times i should need to search for a specific trainingPhrase and if not present then add new training phrase for detected intent. How could i do this using php client library? I am tired of searching on this. Please help me. Any answers will be appreciated. The function I'm using to getIntent with the some text is as below,
function detect_intent_texts($projectId, $text, $sessionId, $languageCode = 'en-US')
{
global $common;
// new session
$test = array('credentials' => 'key_file.json');
$sessionsClient = new SessionsClient($test);
$session = $sessionsClient->sessionName($projectId, $sessionId ?: uniqid());
//printf('Session path: %s' . PHP_EOL, $session);
// create text input
$textInput = new TextInput();
$textInput->setText($text);
$textInput->setLanguageCode($languageCode);
// create query input
$queryInput = new QueryInput();
$queryInput->setText($textInput);
// get response and relevant info
$response = $sessionsClient->detectIntent($session, $queryInput);
$queryResult = $response->getQueryResult();
$queryText = $queryResult->getQueryText();
$intent = $queryResult->getIntent();
$displayName = $intent->getDisplayName();
$common->write_to_log("intent displayName : ".$displayName);
if($displayName == "Default Fallback Intent")
{
$result = json_encode(array("result"=>false));
$common->write_to_log("No matching intent found");
}
else
{
$confidence = $queryResult->getIntentDetectionConfidence();
$fulfilmentText = $queryResult->getFulfillmentText();
$common->write_to_log("intent response : ".$fulfilmentText);
$result = json_encode(array("result"=>true,"message"=>$fulfilmentText));
}
echo $result;
$sessionsClient->close();
}