[HELP] Cancel Order with API Binance / PHP

[hansaplast]

Excuse me first of all for my level of English, the French are null in languages.
I am developing a trading robot but I am having difficulty with the Binance API concerning a cancel order.

The binance API asks me for a SIDE parameter. Out of the binance document, the only SIDE parameters are "BUY" and "SELL"
https://github.com/binance-exchange/bina...est-api.md

In principle, no "SIDE" to cancel an order, despite everything, I have the following result:
Array ([code] => -1102 [msg] => Mandatory parameter 'side' was not sent, was empty / null, or malformed.)

My PHP code is as follows:
$opt = [
"symbol" => "VETBTC",
"orderId" => 12345,
"timestamp" => 1538639865908
];
return $this-> signedRequest ("v3 / order", $opt, "DELETE");

I need a hand :-) Thank you.