diff --git a/cpp/LieConfig-inl.h b/cpp/LieConfig-inl.h
index fdffc2c4d..6bea2d98b 100644
--- a/cpp/LieConfig-inl.h
+++ b/cpp/LieConfig-inl.h
@@ -91,6 +91,11 @@ namespace gtsam {
 	  }
   }
 
+  template<class J, class T>
+  void LieConfig<J,T>::update(const J& j, const T& val) {
+	  	values_[j] = val;
+  }
+
   template<class J, class T>
   std::list<J> LieConfig<J,T>::keys() const {
 	  std::list<J> ret;
diff --git a/cpp/LieConfig.h b/cpp/LieConfig.h
index db650ec7c..acc9bdde7 100644
--- a/cpp/LieConfig.h
+++ b/cpp/LieConfig.h
@@ -100,6 +100,9 @@ namespace gtsam {
     /** update the current available values without adding new ones */
     void update(const LieConfig& cfg);
 
+    /** single element change of existing element */
+    void update(const J& j, const T& val);
+
     /** Remove a variable from the config */
     void erase(const J& j);
 
diff --git a/cpp/testLieConfig.cpp b/cpp/testLieConfig.cpp
index 60c1c5a67..0395fa8bb 100644
--- a/cpp/testLieConfig.cpp
+++ b/cpp/testLieConfig.cpp
@@ -79,6 +79,22 @@ TEST( LieConfig, insert_config )
   CHECK(assert_equal(cfg1, expected));
 }
 
+/* ************************************************************************* */
+TEST( LieConfig, insert_overlap )
+{
+  LieConfig<string,Vector> cfg;
+  Vector v1 = Vector_(3, 5.0, 6.0, 7.0);
+  Vector v2 = Vector_(3, 8.0, 9.0, 1.0);
+
+  cfg.insert("x1", v1);
+  CHECK(cfg.size() == 1);
+  CHECK(assert_equal(v1, cfg.at("x1")));
+
+  cfg.update("x1", v2);
+  CHECK(cfg.size() == 1);
+  CHECK(assert_equal(v2, cfg.at("x1"))); // fails - need to change behavior
+}
+
 /* ************************************************************************* */
 TEST(LieConfig, dim_zero)
 {