diff --git a/prospect.py b/prospect.py
index 5f01ceb..2024f43 100644
--- a/prospect.py
+++ b/prospect.py
@@ -54,7 +54,7 @@ class Prospect(ModelSQL, ModelView, DeactivableMixin):
     @fields.depends('prospect_trace', 'contact_methods')
     def on_change_contact_methods(self):
         for contact in self.contact_methods:
-            contact.prospect_trace = self.prospect_trace
+            contact.update_collaborators(changed_from='prospect')
 
     @fields.depends('city', 'department')
     def on_change_city(self):
@@ -89,6 +89,12 @@ class ContactMethod(ModelSQL, ModelView):
     def default_contact_type(cls):
         return 'mobile'
 
+    def update_collaborators(self, changed_from):
+        if (changed_from == 'prospect'):
+            self.prospect_trace = self.prospect.prospect_trace
+        if (changed_from == 'prospect_trace'):
+            self.prospect = self.prospect_trace.prospect
+
     def get_rec_name(self, name):
         fields = [self.name, self.job, self.value]
         contact_rec_name = ''
diff --git a/prospect_trace.py b/prospect_trace.py
index bab2d8a..ba99546 100644
--- a/prospect_trace.py
+++ b/prospect_trace.py
@@ -52,7 +52,7 @@ class ProspectTrace(ModelSQL, ModelView):
     @fields.depends('prospect_contacts', 'prospect')
     def on_change_prospect_contacts(self):
         for contact in self.prospect_contacts:
-            contact.prospect = self.prospect
+            contact.update_collaborators(changed_from='prospect_trace')
 
     @classmethod
     def __setup__(cls):