diff --git a/easypost/services/shipment_service.py b/easypost/services/shipment_service.py
index 21bf8ccf..4f33aeff 100644
--- a/easypost/services/shipment_service.py
+++ b/easypost/services/shipment_service.py
@@ -154,12 +154,12 @@ def retrieve_estimated_delivery_date(self, id: str, planned_ship_date: str) -> L
 
         return convert_to_easypost_object(response=response.get("rates", []))
 
-    def recommend_ship_date(self, id: str, **params) -> List[Dict[str, Any]]:
+    def recommend_ship_date(self, id: str, desired_delivery_date: str) -> List[Dict[str, Any]]:
         """Retrieve a recommended ship date for an existing Shipment via the Precision Shipping API,
         based on a specific desired delivery date.
         """
         url = f"{self._instance_url(self._model_class, id)}/smartrate/precision_shipping"
-
+        params = {"desired_delivery_date": desired_delivery_date}
         response = Requestor(self._client).request(method=RequestMethod.GET, url=url, params=params)
 
         return convert_to_easypost_object(response=response.get("rates", []))