Not able to Modify order in php

$url = "https://api.kite.trade/orders/regular/".$orderId."?";
        

	$fields = array(
		    api_key => $api_key,
            access_token => $access_token,
            tradingsymbol => $tradingSymbol,
            exchange => $exchange,
            quantity => $quantity,
            transaction_type => $transactionType,
	    	order_type => $orderType,
	    	price => $price1,
		    validity => "DAY",
		    product => "MIS"
            );
            
            
        
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PUT");
        curl_setopt($ch, CURLOPT_POSTFIELDS,http_build_query($fields));
        
        $response = curl_exec($ch);
        curl_close($ch);
        $responsedata = json_decode($response, true);
        echo "<br/>Response after Modify Order: <br/>";
        print_r($responsedata);