diff --git a/api/s1_title.py b/api/s1_title.py
index 2f086c1..3d0e3a3 100644
--- a/api/s1_title.py
+++ b/api/s1_title.py
@@ -1,13 +1,14 @@
 from psycopg.rows import dict_row
 from .operation import *
 from .connection import g_conn_dict as conn
+from .change_set import ChangeSet
 
 def get_title(name: str) -> str:
     with conn[name].cursor(row_factory=dict_row) as cur:
         cur.execute(f"select * from title")
         return cur.fetchone()['value']
 
-def set_title(name: str, value: str) -> None:
+def set_title(name: str, value: str) -> ChangeSet:
     old = get_title(name)
 
     with conn[name].cursor() as cur:
@@ -17,3 +18,7 @@ def set_title(name: str, value: str) -> None:
         redo = sql.replace("'", '"')
         undo = f'update title set value = "{old}"'
         add_operation(name, redo, undo)
+
+    change = ChangeSet()
+    change.update('title', 'null', 'value')
+    return change
diff --git a/api/s2_junctions.py b/api/s2_junctions.py
index 79301ce..0c77405 100644
--- a/api/s2_junctions.py
+++ b/api/s2_junctions.py
@@ -2,8 +2,9 @@ from psycopg.rows import dict_row, Row
 from .connection import g_conn_dict as conn
 from .s0_base import *
 from .operation import *
+from .change_set import ChangeSet
 
-def add_junction(name: str, id: str, x: float, y: float, elevation: float) -> None:
+def add_junction(name: str, id: str, x: float, y: float, elevation: float) -> ChangeSet:
     if is_node(name, id):
         return
 
@@ -19,7 +20,12 @@ def add_junction(name: str, id: str, x: float, y: float, elevation: float) -> No
         undo += f' delete from _node where id = "{id}";'
         add_operation(name, redo, undo)
 
-def delete_junction(name: str, id: str) -> None:
+    change = ChangeSet()
+    change.add('junction', id)
+    return change
+
+
+def delete_junction(name: str, id: str) -> ChangeSet:
     if not is_junction(name, id):
         return
 
@@ -52,6 +58,11 @@ def delete_junction(name: str, id: str) -> None:
         undo += f"  insert into coordinates (node, coord) values ('{id}', '{coord}');"
         add_operation(name, redo, undo)
 
+    change = ChangeSet()
+    change.delete('junction', id)
+    return change
+
+
 def _get_junction(name: str, id: str) -> Row | None:
     with conn[name].cursor(row_factory=dict_row) as cur:
         cur.execute(f"select elevation, demand, pattern from junctions where id = '{id}'")
@@ -91,7 +102,7 @@ def get_junction_coord(name: str, id: str) -> dict[str, float] | None:
         coord = str(row['coord'])
         return _to_point(coord)
 
-def set_junction_elevation(name: str, id: str, elevation: float) -> None:
+def set_junction_elevation(name: str, id: str, elevation: float) -> ChangeSet:
     if not is_junction(name, id):
         return
 
@@ -106,7 +117,12 @@ def set_junction_elevation(name: str, id: str, elevation: float) -> None:
         undo = f'update junctions set elevation = {old} where id = "{id}"'
         add_operation(name, redo, undo)
 
-def set_junction_demand(name: str, id: str, demand: float) -> None:
+    change = ChangeSet()
+    change.update('junction', id, 'elevation')
+    return change
+
+
+def set_junction_demand(name: str, id: str, demand: float) -> ChangeSet:
     if not is_junction(name, id):
         return
 
@@ -121,7 +137,12 @@ def set_junction_demand(name: str, id: str, demand: float) -> None:
         undo = f'update junctions set demand = {old} where id = "{id}"'
         add_operation(name, redo, undo)
 
-def set_junction_pattern(name: str, id: str, pattern: str) -> None:
+    change = ChangeSet()
+    change.update('junction', id, 'demand')
+    return change
+
+
+def set_junction_pattern(name: str, id: str, pattern: str) -> ChangeSet:
     if not is_junction(name, id):
         return
     if not is_pattern(name, id):
@@ -140,7 +161,12 @@ def set_junction_pattern(name: str, id: str, pattern: str) -> None:
         undo = f'update junctions set pattern = {old} where id = "{id}"'
         add_operation(name, redo, undo)
 
-def set_junction_coord(name: str, id: str, x: float, y: float) -> None:
+    change = ChangeSet()
+    change.update('junction', id, 'pattern')
+    return change
+
+
+def set_junction_coord(name: str, id: str, x: float, y: float) -> ChangeSet:
     if not is_junction(name, id):
         return
 
@@ -156,3 +182,7 @@ def set_junction_coord(name: str, id: str, x: float, y: float) -> None:
         redo = sql.replace("'", '"')
         undo = f'update coordinates set coord = "({old_x},{old_y})" where node = "{id}"'
         add_operation(name, redo, undo)
+
+    change = ChangeSet()
+    change.update('junction', id, 'coord')
+    return change
diff --git a/tjnetwork_new.py b/tjnetwork_new.py
index e3661a8..c47d573 100644
--- a/tjnetwork_new.py
+++ b/tjnetwork_new.py
@@ -1,3 +1,4 @@
+from msilib.schema import CheckBox
 import api
 
 
@@ -128,7 +129,7 @@ def get_patterns(name: str) -> list[str]:
 # title 1.[TITLE]
 ############################################################
 
-def set_title(name: str, title: str) -> None:
+def set_title(name: str, title: str) -> ChangeSet:
     return api.set_title(name, title)
 
 def get_title(name: str) -> str:
@@ -139,10 +140,10 @@ def get_title(name: str) -> str:
 # junction 2.[JUNCTIONS]
 ############################################################
 
-def add_junction(name: str, junction_id: str, x: float, y: float, elevation: float) -> None:
+def add_junction(name: str, junction_id: str, x: float, y: float, elevation: float) -> ChangeSet:
     return api.add_junction(name, junction_id, x, y, elevation)
 
-def delete_junction(name: str, junction_id: str) -> None:
+def delete_junction(name: str, junction_id: str) -> ChangeSet:
     return api.delete_junction(name, junction_id)
 
 def get_junction_elevation(name: str, junction_id: str) -> float | None:
@@ -157,14 +158,14 @@ def get_junction_pattern(name: str, junction_id: str) -> str | None:
 def get_junction_coord(name: str, junction_id: str) -> dict[str, float] | None:
     return api.get_junction_coord(name, junction_id)
 
-def set_junction_elevation(name: str, junction_id: str, elevation: float) -> None:
+def set_junction_elevation(name: str, junction_id: str, elevation: float) -> ChangeSet:
     return api.set_junction_elevation(name, junction_id, elevation)
 
-def set_junction_demand(name: str, junction_id: str, demand: float) -> None:
+def set_junction_demand(name: str, junction_id: str, demand: float) -> ChangeSet:
     return api.set_junction_demand(name, junction_id, demand)
 
-def set_junction_pattern(name: str, junction_id: str, pattern: str) -> None:
+def set_junction_pattern(name: str, junction_id: str, pattern: str) -> ChangeSet:
     return api.set_junction_pattern(name, junction_id, pattern)
 
-def set_junction_coord(name: str, junction_id: str, x: float, y: float) -> None:
+def set_junction_coord(name: str, junction_id: str, x: float, y: float) -> ChangeSet:
     return api.set_junction_coord(name, junction_id, x, y)