diff --git a/CHANGELOG.md b/CHANGELOG.md
index 35ad6a2d4..c1f4b18e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,10 +1,12 @@
 # Changelog Fab-manager
 
+- Fix a bug: members can't change/cancel their reservations
+
 ## v5.7.2 2023 February 24
 
 - Fix a bug: unable to update recurrent events
 - Fix a bug: invalid border color for slots
-- Fix a bug: members can change/cancel their reservations
+- Fix a bug: members can't change/cancel their reservations
 
 ## v5.7.1 2023 February 20
 
diff --git a/app/views/api/availabilities/_slot.json.jbuilder b/app/views/api/availabilities/_slot.json.jbuilder
index 70f3b3f2c..b9afa9923 100644
--- a/app/views/api/availabilities/_slot.json.jbuilder
+++ b/app/views/api/availabilities/_slot.json.jbuilder
@@ -10,7 +10,7 @@ json.is_completed slot.full?(reservable)
 json.backgroundColor 'white'
 
 json.availability_id slot.availability_id
-json.slots_reservations_ids Slots::ReservationsService.user_reservations(slot, user, reservable)[:reservations]
+json.slots_reservations_ids Slots::ReservationsService.user_reservations(slot, user, reservable)[:reservations].map(&:id)
 
 json.tag_ids slot.availability.tag_ids
 json.tags slot.availability.tags do |t|