diff --git a/streetup/interventions/tests/test_calendar.py b/streetup/interventions/tests/test_calendar.py
index 228ddc6..7d0ee83 100644
--- a/streetup/interventions/tests/test_calendar.py
+++ b/streetup/interventions/tests/test_calendar.py
@@ -290,6 +290,32 @@ class CalendarEventsTests(TestCase):
         self.assertTrue(len(data['team_history']) >= 1)
         self.assertEqual(data['team_history'][0]['team_name'], self.team_a.name)
 
+    def test_unassign_sans_equipe_reverts_status_to_backlog(self):
+        itv = Intervention.objects.create(
+            title='Unassigned Test',
+            status='to_be_processed',
+            maintain_type='corrective',
+            priority='2',
+            planned_begin_time=timezone.now(),
+            planned_end_time=timezone.now() + timedelta(hours=2),
+        )
+        url = reverse('interventions:interventions_schedule_update')
+        payload = {
+            'intervention_id': itv.id,
+            'member_id': None,
+            'team_id': None,
+            'unassign': True,
+        }
+        response = self.client.post(url, json.dumps(payload), content_type='application/json')
+        self.assertEqual(response.status_code, 200)
+
+        itv.refresh_from_db()
+        self.assertEqual(itv.status, 'to_be_planned')
+        self.assertIsNone(itv.planned_begin_time)
+        self.assertIsNone(itv.planned_end_time)
+        self.assertIsNone(itv.assigned_team)
+        self.assertIsNone(itv.assigned_member)
+
 
 
 
diff --git a/streetup/interventions/views/calendar.py b/streetup/interventions/views/calendar.py
index 9946380..9eb7d8a 100644
--- a/streetup/interventions/views/calendar.py
+++ b/streetup/interventions/views/calendar.py
@@ -1213,14 +1213,20 @@ def interventions_schedule_update(request):
     if planned_end and is_naive(planned_end):
         planned_end = make_aware(planned_end, tz)
 
-    if not planned_begin:
-        return JsonResponse({'error': _('La date de début planifiée est obligatoire.')}, status=400)
-    if planned_begin.date() < timezone.now().date():
-        return JsonResponse({'error': _("Il est interdit de planifier ou d'assigner une intervention dans le passé.")}, status=400)
-    if not planned_end:
-        planned_end = planned_begin + timedelta(hours=2)
-    if planned_end <= planned_begin:
-        return JsonResponse({'error': _('La fin planifiée doit être postérieure au début planifié.')}, status=400)
+    unassign = payload.get('unassign', False) or payload.get('to_backlog', False) or (member_key_present and team_key_present and not member_id and not team_id)
+
+    if not unassign:
+        if not planned_begin:
+            return JsonResponse({'error': _('La date de début planifiée est obligatoire.')}, status=400)
+        if planned_begin.date() < timezone.now().date():
+            return JsonResponse({'error': _("Il est interdit de planifier ou d'assigner une intervention dans le passé.")}, status=400)
+        if not planned_end:
+            planned_end = planned_begin + timedelta(hours=2)
+        if planned_end <= planned_begin:
+            return JsonResponse({'error': _('La fin planifiée doit être postérieure au début planifié.')}, status=400)
+    else:
+        planned_begin = None
+        planned_end = None
 
     prev_begin = intervention.planned_begin_time
     prev_end = intervention.planned_end_time
@@ -1256,13 +1262,13 @@ def interventions_schedule_update(request):
     
     # Check if intervention is being assigned (to member or team)
     is_now_assigned = intervention.assigned_member_id is not None or intervention.assigned_team_id is not None
-    was_assigned = prev_member_id is not None or prev_team_id is not None
+    is_unassigning = unassign or (not is_now_assigned)
     
     # If intervention was "to_be_planned" and is now assigned -> change to "to_be_processed"
     if prev_status == 'to_be_planned' and is_now_assigned:
         new_status = 'to_be_processed'
     # If intervention is being unassigned (back to backlog) -> change to "to_be_planned"
-    elif was_assigned and not is_now_assigned and prev_status in ('to_be_processed', 'assigned'):
+    elif is_unassigning and prev_status in ('to_be_processed', 'assigned'):
         new_status = 'to_be_planned'
     
     if new_status != prev_status: