diff --git a/CHANGELOG.md b/CHANGELOG.md
index 918ef12f2..8609fdaa1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Next release
 
+- Fix a bug: unable to change training reservation slot to another slot
+
 ## v6.3.29 2024 July 19
 
 - updates chinese translations and adds translations
diff --git a/app/frontend/src/javascript/controllers/trainings.js.erb b/app/frontend/src/javascript/controllers/trainings.js.erb
index ae6671111..b0496d164 100644
--- a/app/frontend/src/javascript/controllers/trainings.js.erb
+++ b/app/frontend/src/javascript/controllers/trainings.js.erb
@@ -393,7 +393,7 @@ Application.Controllers.controller('ReserveTrainingController', ['$scope', '$tra
      */
     const refreshCalendar = function () {
       $scope.eventSources.splice(0, 1, {
-        url: `/api/availabilities/trainings/${$transition$.params().id}`,
+        url: `/api/availabilities/trainings/${$transition$.params().id}?member_id=${$scope.ctrl.member.id}`,
         textColor: 'black'
       });
     }