diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c0af050b..f084ee39f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## next release
 
+- fix a bug: fix event service
 
 ## v6.3.5 2023 December 4
 
diff --git a/app/services/event_service.rb b/app/services/event_service.rb
index dd24fbc3a..b41ef36bd 100644
--- a/app/services/event_service.rb
+++ b/app/services/event_service.rb
@@ -28,7 +28,7 @@ class EventService
           price_cat[:amount] = to_centimes(price_cat[:amount])
         end
       end
-      params[:pre_registration_end_date] = Date.parse(params[:pre_registration_end_date]).end_of_day if params[:pre_registration_end_date]
+      params[:pre_registration_end_date] = Date.parse(params[:pre_registration_end_date]).end_of_day if params[:pre_registration_end_date].present?
       # return the resulting params object
       params
     end