diff --git a/fediseer/database/functions.py b/fediseer/database/functions.py
index 114085d..d569114 100644
--- a/fediseer/database/functions.py
+++ b/fediseer/database/functions.py
@@ -49,7 +49,7 @@ def get_all_endorsed_instances_by_approving_id(approving_ids):
     )
     return query.all()
 
-def get_all_approving_instances_by_endorsed_id(endorsed_ids):
+def get_all_approving_instances_by_endorsed_id(endorsed_id):
     query = db.session.query(
         Instance
     ).outerjoin(
@@ -57,7 +57,7 @@ def get_all_approving_instances_by_endorsed_id(endorsed_ids):
     ).options(
         joinedload(Instance.approvals),
     ).filter(
-        Endorsement.endorsed_id.in_(endorsed_ids)
+        Endorsement.endorsed_id == endorsed_id
     ).group_by(
         Instance.id
     )