diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index afae738c7e0..5266e9a9fac 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -150,7 +150,7 @@ function pingPong($stub) {
 }
 
 function cancelAfterFirstResponse($stub) {
-  $call = $stub->StreamingInputCall();
+  $call = $stub->FullDuplexCall();
   $request = new grpc\testing\StreamingOutputCallRequest();
   $request->setResponseType(grpc\testing\PayloadType::COMPRESSABLE);
   $response_parameters = new grpc\testing\ResponseParameters();