diff --git a/lib/Request.php b/lib/Request.php
index 3442c53..00f7993 100644
--- a/lib/Request.php
+++ b/lib/Request.php
@@ -20,7 +20,7 @@ abstract class Request
      *
      * @return mixed API Request response in requested data format.
      */
-    public static function request($request, $output_format = "xml", $decode_json = false)
+    public static function request($request, $output_format = "xml", $decode_json = false, $additional_headers = array())
     {
         \RESO\RESO::logMessage("Sending request '".$request."' to RESO API.");
 
@@ -53,6 +53,8 @@ public static function request($request, $output_format = "xml", $decode_json =
             "Authorization: Bearer ".$token
         );
 
+        $headers = array_merge($additional_headers, $headers);
+
         // Send request
         $response = $curl->request("get", $url, $headers, null, false);
         if(!$response || !is_array($response) || $response[1] != 200) {