diff --git a/src/ifcopenshell-python/test/api/root/test_reassign_class.py b/src/ifcopenshell-python/test/api/root/test_reassign_class.py
index 3049b4cd3b..fc9a7f4b2b 100644
--- a/src/ifcopenshell-python/test/api/root/test_reassign_class.py
+++ b/src/ifcopenshell-python/test/api/root/test_reassign_class.py
@@ -50,3 +50,45 @@ class TestReassignClass(test.bootstrap.IFC4):
         )
         assert new.PredefinedType == "USERDEFINED"
         assert new.ElementType == "FOO"
+
+    def test_reassign_class_for_type_occurrences(self):
+        element_type = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWallType")
+        element1 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        ifcopenshell.api.run("type.assign_type", self.file, related_object=element1, relating_type=element_type)
+        element2 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        ifcopenshell.api.run("type.assign_type", self.file, related_object=element2, relating_type=element_type)
+
+        element_type = ifcopenshell.api.run(
+            "root.reassign_class", self.file, product=element_type, ifc_class="IfcSlabType"
+        )
+
+        # type occurrences have reassigned classes
+        occurrences = ifcopenshell.util.element.get_types(element_type)
+        assert len(occurrences) == 2
+        assert all(o.is_a("IfcSlab") for o in occurrences)
+
+        # original clases are gone
+        assert len(self.file.by_type("IfcWall")) == 0
+        assert len(self.file.by_type("IfcWallType")) == 0
+
+    def test_reassigning_type_class_and_its_occurrences_classes_if_entity_was_typed(self):
+        element_type = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWallType")
+        element1 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        ifcopenshell.api.run("type.assign_type", self.file, related_object=element1, relating_type=element_type)
+        element2 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        ifcopenshell.api.run("type.assign_type", self.file, related_object=element2, relating_type=element_type)
+
+        element1 = ifcopenshell.api.run("root.reassign_class", self.file, product=element1, ifc_class="IfcSlab")
+
+        # occurrence type has reassigned class
+        element_type = ifcopenshell.util.element.get_type(element1)
+        assert element_type.is_a("IfcSlabType")
+
+        # other type occurrences have reassigned classes
+        occurrences = ifcopenshell.util.element.get_types(element_type)
+        assert len(occurrences) == 2
+        assert all(o.is_a("IfcSlab") for o in occurrences)
+
+        # original clases are gone
+        assert len(self.file.by_type("IfcWall")) == 0
+        assert len(self.file.by_type("IfcWallType")) == 0