setUsername("YOUR_API_KEY"); // or, configure Bearer (JWT) authorization: oauth2 // $config->setAccessToken("YOUR_ACCESS_TOKEN"); $api = new HelloSignSDK\Api\SignatureRequestApi($config); $signatureRequestId = "2f9781e1a8e2045224d808c153c2e1d3df6f8f2f"; try { $api->signatureRequestCancel($signatureRequestId); } catch (HelloSignSDK\ApiException $e) { $error = $e->getResponseObject(); echo "Exception when calling HelloSign API: " . print_r($error->getError()); }