diff --git a/eeschema/connection_graph.cpp b/eeschema/connection_graph.cpp
index f992498c4f..a21db33bdd 100644
--- a/eeschema/connection_graph.cpp
+++ b/eeschema/connection_graph.cpp
@@ -85,6 +85,47 @@ void CONNECTION_SUBGRAPH::RemoveItem( SCH_ITEM* aItem )
 }
 
 
+void CONNECTION_SUBGRAPH::ExchangeItem( SCH_ITEM* aOldItem, SCH_ITEM* aNewItem )
+{
+    m_items.erase( aOldItem );
+    m_items.insert( aNewItem );
+
+    m_drivers.erase( aOldItem );
+    m_drivers.insert( aNewItem );
+
+    if( aOldItem == m_driver )
+    {
+        m_driver = aNewItem;
+        m_driver_connection = aNewItem->GetOrInitConnection( m_sheet, m_graph );
+    }
+
+    SCH_CONNECTION* old_conn = aOldItem->Connection( &m_sheet );
+    SCH_CONNECTION* new_conn = aNewItem->GetOrInitConnection( m_sheet, m_graph );
+
+    if( old_conn && new_conn )
+    {
+        new_conn->Clone( *old_conn );
+
+        if( old_conn->IsDriver() )
+            new_conn->SetDriver( aNewItem );
+
+        new_conn->ClearDirty();
+    }
+
+    if( aOldItem->Type() == SCH_SHEET_PIN_T )
+    {
+        m_hier_pins.erase( static_cast<SCH_SHEET_PIN*>( aOldItem ) );
+        m_hier_pins.insert( static_cast<SCH_SHEET_PIN*>( aNewItem ) );
+    }
+
+    if( aOldItem->Type() == SCH_HIER_LABEL_T )
+    {
+        m_hier_ports.erase( static_cast<SCH_HIERLABEL*>( aOldItem ) );
+        m_hier_ports.insert( static_cast<SCH_HIERLABEL*>( aNewItem ) );
+    }
+}
+
+
 bool CONNECTION_SUBGRAPH::ResolveDrivers( bool aCheckMultipleDrivers )
 {
     std::lock_guard lock( m_driver_mutex );
@@ -576,6 +617,53 @@ void CONNECTION_GRAPH::Merge( CONNECTION_GRAPH& aGraph )
 }
 
 
+void CONNECTION_GRAPH::ExchangeItem( SCH_ITEM* aOldItem, SCH_ITEM* aNewItem )
+{
+    wxCHECK2( aOldItem->Type() == aNewItem->Type(), return );
+
+    auto exchange = [&]( SCH_ITEM* aOld, SCH_ITEM* aNew )
+    {
+        auto it = m_item_to_subgraph_map.find( aOld );
+
+        if( it == m_item_to_subgraph_map.end() )
+            return;
+
+        CONNECTION_SUBGRAPH* sg = it->second;
+
+        sg->ExchangeItem( aOld, aNew );
+
+        m_item_to_subgraph_map.erase( it );
+        m_item_to_subgraph_map.emplace( aNew, sg );
+
+        for( auto it2 = m_items.begin(); it2 != m_items.end(); ++it2 )
+        {
+            if( *it2 == aOld )
+            {
+                *it2 = aNew;
+                break;
+            }
+        }
+    };
+
+    exchange( aOldItem, aNewItem );
+
+    if( aOldItem->Type() == SCH_SYMBOL_T )
+    {
+        SCH_SYMBOL* oldSymbol = static_cast<SCH_SYMBOL*>( aOldItem );
+        SCH_SYMBOL* newSymbol = static_cast<SCH_SYMBOL*>( aNewItem );
+        std::vector<SCH_PIN*> oldPins = oldSymbol->GetPins( &m_schematic->CurrentSheet() );
+        std::vector<SCH_PIN*> newPins = newSymbol->GetPins( &m_schematic->CurrentSheet() );
+
+        wxCHECK2( oldPins.size() == newPins.size(), return );
+
+        for( size_t ii = 0; ii < oldPins.size(); ii++ )
+        {
+            exchange( oldPins[ii], newPins[ii] );
+        }
+    }
+}
+
+
 void CONNECTION_GRAPH::Reset()
 {
     for( auto& subgraph : m_subgraphs )
diff --git a/eeschema/connection_graph.h b/eeschema/connection_graph.h
index 884f09b1b4..d930ab819b 100644
--- a/eeschema/connection_graph.h
+++ b/eeschema/connection_graph.h
@@ -199,6 +199,11 @@ public:
 
     void RemoveItem( SCH_ITEM* aItem );
 
+    /**
+     * Replaces all references to #aOldItem with #aNewItem in the subgraph.
+    */
+    void ExchangeItem( SCH_ITEM* aOldItem, SCH_ITEM* aNewItem );
+
     // Use this to keep a connection pointer that is not owned by any item
     // This will be destroyed with the subgraph
     void StoreImplicitConnection( SCH_CONNECTION* aConnection )
@@ -456,6 +461,11 @@ public:
 
     void RemoveItem( SCH_ITEM* aItem );
 
+    /**
+     * Replace all references to #aOldItem with #aNewItem in the graph.
+    */
+    void ExchangeItem( SCH_ITEM* aOldItem, SCH_ITEM* aNewItem );
+
 private:
     /**
      * Update the graphical connectivity between items (i.e. where they touch)
diff --git a/eeschema/dialogs/dialog_change_symbols.cpp b/eeschema/dialogs/dialog_change_symbols.cpp
index c66f8ea0ba..f40151d38b 100644
--- a/eeschema/dialogs/dialog_change_symbols.cpp
+++ b/eeschema/dialogs/dialog_change_symbols.cpp
@@ -23,6 +23,7 @@
 #include <algorithm>
 
 #include <bitmaps.h>
+#include <connection_graph.h>
 #include <string_utils.h>   // WildCompareString
 #include <kiway.h>
 #include <refdes_utils.h>
@@ -602,7 +603,17 @@ int DIALOG_CHANGE_SYMBOLS::processSymbols( SCH_COMMIT* aCommit,
         wxCHECK( screen, 0 );
 
         screen->Remove( symbol );
-        aCommit->Modify( symbol, screen );
+        SCH_SYMBOL* symbol_copy = static_cast<SCH_SYMBOL*>( symbol->Clone() );
+        aCommit->Modified( symbol, symbol_copy, screen );
+
+        CONNECTION_GRAPH*           connectionGraph = screen->Schematic()->ConnectionGraph();
+
+        // When we replace the lib symbol below, we free the associated pins if the new symbol has
+        // fewer than the original.  This will cause the connection graph to be out of date unless
+        // we replace references in the graph to the old symbol/pins with references to the ones stored
+        // in the undo stack.
+        if( connectionGraph )
+            connectionGraph->ExchangeItem( symbol, symbol_copy );
     }
 
     for( const auto& [ symbol, symbol_change_info ] : symbols )
diff --git a/eeschema/sch_edit_frame.cpp b/eeschema/sch_edit_frame.cpp
index ba5148430e..9f25b6629c 100644
--- a/eeschema/sch_edit_frame.cpp
+++ b/eeschema/sch_edit_frame.cpp
@@ -1718,7 +1718,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_COMMIT* aCommit, SCH_CLEANUP_FL
     {
         PICKED_ITEMS_LIST* changed_list = m_undoList.m_CommandsList.back();
         std::set<SCH_ITEM*> changed_items;
-        std::vector<VECTOR2I> pts;
+        std::set<VECTOR2I> pts;
         std::set<std::pair<SCH_SHEET_PATH, SCH_ITEM*>> item_paths;
 
         for( unsigned ii = 0; ii < changed_list->GetCount(); ++ii )
@@ -1733,7 +1733,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_COMMIT* aCommit, SCH_CLEANUP_FL
             SCH_SHEET_PATHS& paths = screen->GetClientSheetPaths();
 
             std::vector<VECTOR2I> tmp_pts = item->GetConnectionPoints();
-            pts.insert( pts.end(), tmp_pts.begin(), tmp_pts.end() );
+            pts.insert( tmp_pts.begin(), tmp_pts.end() );
             changed_items.insert( item );
 
             for( SCH_SHEET_PATH& path : paths )
@@ -1745,7 +1745,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_COMMIT* aCommit, SCH_CLEANUP_FL
                 continue;
 
             tmp_pts = item->GetConnectionPoints();
-            pts.insert( pts.end(), tmp_pts.begin(), tmp_pts.end() );
+            pts.insert( tmp_pts.begin(), tmp_pts.end() );
             changed_items.insert( item );
 
             // We have to directly add the pins here because the link may not exist on the schematic
@@ -1760,7 +1760,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_COMMIT* aCommit, SCH_CLEANUP_FL
                 item_paths.insert( std::make_pair( path, item ) );
         }
 
-        for( VECTOR2I& pt: pts )
+        for( const VECTOR2I& pt: pts )
         {
             for( SCH_ITEM* item : GetScreen()->Items().Overlapping( pt ) )
             {
diff --git a/include/commit.h b/include/commit.h
index 3e5d085114..c67204dae4 100644
--- a/include/commit.h
+++ b/include/commit.h
@@ -111,7 +111,7 @@ public:
     ///< before the modification.
     COMMIT& Modified( EDA_ITEM* aItem, EDA_ITEM* aCopy, BASE_SCREEN *aScreen = nullptr )
     {
-        return createModified( aItem, aCopy );
+        return createModified( aItem, aCopy, 0, aScreen );
     }
 
     template<class Range>