diff --git a/ch16/ex16_28_unique_ptr.h b/ch16/ex16_28_unique_ptr.h
index f58efc23..4cbd315a 100644
--- a/ch16/ex16_28_unique_ptr.h
+++ b/ch16/ex16_28_unique_ptr.h
@@ -45,7 +45,8 @@ template <typename T, typename D = Delete> class UniquePtr {
 
     void reset(T* q = nullptr) noexcept
     {
-        deleter_(q);
+        deleter_(q);        // Error: should relase old obj pointed by ptr
+        // deleter_(ptr);   // Corrected !!
         ptr_ = q;
     }
 
@@ -69,4 +70,4 @@ template <typename T, typename D = Delete> class UniquePtr {
     D deleter_;
 };
 
-#endif // CP5_EX16_28_UNIQUE_PTR_H_
\ No newline at end of file
+#endif // CP5_EX16_28_UNIQUE_PTR_H_