To document the cancellation function, we'll cover the purpose of the function, how to use it, the required parameters, and the format of the response. This function handles the cancellation of a transaction or part of a transaction within a payment system, utilizing XML for request and response data communication.

Example:

use Stegback\Ratepay\Services\RatepayReturn;
{
        $product = [
            'total_amount' => '1000.00', // if you want full cancellation make amount 0;
            // item not required in the case of full cancellation only mentaion that product which you want to cancel
            'item' => [
                [
                    'product_id' => 1,
                    'product_quantity' => 1,
                    'product_price' => 10,
                    'product_name' => 'Article A',
                ],
            ],
            'discount' => 0, // if any define here
        ];
        $ratepay = new RatepayReturn;
        $response = $ratepay->cancellation(string 'full | partial',array $product,string 'your_genrated_transaction_id');
        return $response;
    }