diff --git a/core/apps/orders/serializers/party.py b/core/apps/orders/serializers/party.py
index ac09147..97160e6 100644
--- a/core/apps/orders/serializers/party.py
+++ b/core/apps/orders/serializers/party.py
@@ -350,7 +350,7 @@ class PartyUpdateSerializer(serializers.ModelSerializer):
                     "project",
                 ],
             )
-            party_amount = PartyAmount.objects.get(party=party)
+            party_amount = PartyAmount.objects.get(party=instance)
             party_amount.total_price = total_price
             party_amount.cost_amount = total_price - party.discount
             party_amount.payment_amount = total_price - party.discount