diff --git a/src/Request/BaseRequest.php b/src/Request/BaseRequest.php
index 08d2c53..a6baf00 100644
--- a/src/Request/BaseRequest.php
+++ b/src/Request/BaseRequest.php
@@ -11,6 +11,8 @@ abstract class BaseRequest
 
     /** @var string */
     protected $method;
+    
+    protected bool $simulationMode;
 
     /**
      * @return string
@@ -27,6 +29,11 @@ public function getUri(): string
     {
         return $this->uri;
     }
+    
+    public function setSimulationMode(bool $mode): void
+    {
+        $this->simulationMode = $mode;
+    }   
 
     abstract public function getQueryArray(): array;
 
diff --git a/src/Request/VocalCampaign/SendVocalCampaignRequest.php b/src/Request/VocalCampaign/SendVocalCampaignRequest.php
index 173ae18..da23e11 100644
--- a/src/Request/VocalCampaign/SendVocalCampaignRequest.php
+++ b/src/Request/VocalCampaign/SendVocalCampaignRequest.php
@@ -59,6 +59,7 @@ public function getQueryArray(): array
                 'voice_gender' => $this->voiceGender,
                 'voice_language' => $this->voiceLanguage,
                 'send_at' => $this->sendAt,
+                'simulation_mode' => $this->simulationMode,
             ],
         ];