diff --git a/db/migrate/20200625081552_add_unique_index_to_lookup_value.rb b/db/migrate/20200625081552_add_unique_index_to_lookup_value.rb
index 8461ce26da9..736cc1fb6ad 100644
--- a/db/migrate/20200625081552_add_unique_index_to_lookup_value.rb
+++ b/db/migrate/20200625081552_add_unique_index_to_lookup_value.rb
@@ -1,5 +1,13 @@
 class AddUniqueIndexToLookupValue < ActiveRecord::Migration[6.0]
-  def change
+  def up
+    LookupValue.where.not(id: LookupValue.group(:lookup_key_id, :match).select('MAX(id)')).each do |lookup_value|
+      say "Deleting duplicate override value for #{lookup_value.lookup_key.class.humanize_class_name} #{lookup_value.lookup_key.key} with matcher #{lookup_value.match} and value #{lookup_value.value}"
+      lookup_value.destroy
+    end
     add_index :lookup_values, [:lookup_key_id, :match], unique: true
   end
+
+  def down
+    remove_index :lookup_values, column: [:lookup_key_id, :match], unique: true
+  end
 end