diff --git a/engine/apps/api/serializers/on_call_shifts.py b/engine/apps/api/serializers/on_call_shifts.py
index 15fe1a78..794c466f 100644
--- a/engine/apps/api/serializers/on_call_shifts.py
+++ b/engine/apps/api/serializers/on_call_shifts.py
@@ -46,7 +46,6 @@ class OnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer):
             "until",
             "frequency",
             "interval",
-            "until",
             "by_day",
             "source",
             "rolling_users",
@@ -74,7 +73,7 @@ class OnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer):
         result = super().to_representation(instance)
         return result
 
-    def validate_name(self, name):  # todo
+    def validate_name(self, name):
         organization = self.context["request"].auth.organization
         if name is None:
             return name
@@ -147,12 +146,15 @@ class OnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer):
             "interval",
             "by_day",
             "until",
+            "rotation_start",
         ]
         if event_type == CustomOnCallShift.TYPE_OVERRIDE:
             for field in fields_to_update_for_overrides:
                 value = None
                 if field == "priority_level":
                     value = 0
+                elif field == "rotation_start":
+                    value = validated_data["start"]
                 validated_data[field] = value
 
         self._validate_frequency(
diff --git a/engine/apps/schedules/migrations/0006_customoncallshift_rotation_start.py b/engine/apps/schedules/migrations/0006_customoncallshift_rotation_start.py
index 9facd79b..682df514 100644
--- a/engine/apps/schedules/migrations/0006_customoncallshift_rotation_start.py
+++ b/engine/apps/schedules/migrations/0006_customoncallshift_rotation_start.py
@@ -1,17 +1,12 @@
 # Generated by Django 3.2.13 on 2022-07-12 08:03
 
 from django.db import migrations, models
+from django.db.models import F
 
 
 def fill_rotation_start_field(apps, schema_editor):
     CustomOnCallShift = apps.get_model("schedules", "CustomOnCallShift")
-    shifts = CustomOnCallShift.objects.all()
-    shifts_to_update = []
-    for shift in shifts:
-        shift.rotation_start = shift.start
-        shifts_to_update.append(shift)
-
-    CustomOnCallShift.objects.bulk_update(shifts_to_update, ["rotation_start"], batch_size=5000)
+    CustomOnCallShift.objects.update(rotation_start=F("start"))
 
 
 class Migration(migrations.Migration):
diff --git a/engine/apps/schedules/models/custom_on_call_shift.py b/engine/apps/schedules/models/custom_on_call_shift.py
index 15c35da8..64d72ae8 100644
--- a/engine/apps/schedules/models/custom_on_call_shift.py
+++ b/engine/apps/schedules/models/custom_on_call_shift.py
@@ -236,7 +236,8 @@ class CustomOnCallShift(models.Model):
             result += (
                 f", frequency: {self.get_frequency_display()}, interval: {self.interval}, "
                 f"week start: {self.week_start}, by day: {self.by_day}, by month: {self.by_month}, "
-                f"by monthday: {self.by_monthday}, until: {self.until.isoformat() if self.until else None}"
+                f"by monthday: {self.by_monthday}, rotation start: {self.rotation_start.isoformat()}, "
+                f"until: {self.until.isoformat() if self.until else None}"
             )
         return result