diff --git a/app/frontend/src/javascript/controllers/machines.js.erb b/app/frontend/src/javascript/controllers/machines.js.erb
index deb7a41ed..c7d026334 100644
--- a/app/frontend/src/javascript/controllers/machines.js.erb
+++ b/app/frontend/src/javascript/controllers/machines.js.erb
@@ -480,6 +480,7 @@ Application.Controllers.controller('ReserveMachineController', ['$scope', '$tran
      */
     $scope.markSlotAsModifying = function () {
       $scope.selectedEvent.backgroundColor = '#eee';
+      $scope.selectedEvent.oldTitle = $scope.selectedEvent.title;
       $scope.selectedEvent.title = _t('app.logged.machines_reserve.i_change');
       updateEvents($scope.selectedEvent);
     };
@@ -508,8 +509,8 @@ Application.Controllers.controller('ReserveMachineController', ['$scope', '$tran
       const save = {
         slotId: $scope.events.modifiable.slot_id,
         borderColor: $scope.events.modifiable.borderColor,
-        user: angular.copy($scope.events.modifiable.user),
-        title: (!$scope.events.modifiable.user || $scope.currentUser.id === $scope.events.modifiable.user.id) ? _t('app.logged.machines_reserve.i_ve_reserved') : _t('app.logged.machines_reserve.not_available')
+        users: angular.copy($scope.events.modifiable.users),
+        title: (!$scope.events.modifiable.users || $scope.events.modifiable.users.map(u => u.id).includes($scope.currentUser.id)) ? _t('app.logged.machines_reserve.i_ve_reserved') : _t('app.logged.machines_reserve.not_available')
       };
 
       $scope.events.modifiable.backgroundColor = 'white';
@@ -526,7 +527,7 @@ Application.Controllers.controller('ReserveMachineController', ['$scope', '$tran
       $scope.events.placable.slot_id = save.slotId;
       $scope.events.placable.is_reserved = true;
       $scope.events.placable.can_modify = true;
-      $scope.events.placable.user = angular.copy(save.user);
+      $scope.events.placable.users = angular.copy(save.users);
       updateEvents($scope.events.placable);
 
       refetchCalendar();
@@ -540,7 +541,7 @@ Application.Controllers.controller('ReserveMachineController', ['$scope', '$tran
         $scope.events.placable.backgroundColor = 'white';
         $scope.events.placable.title = '';
       }
-      $scope.events.modifiable.title = $scope.currentUser.id === $scope.events.modifiable.user.id ? _t('app.logged.machines_reserve.i_ve_reserved') : _t('app.logged.machines_reserve.not_available');
+      $scope.events.modifiable.title = $scope.events.modifiable.oldTitle;
       $scope.events.modifiable.backgroundColor = 'white';
 
       updateEvents($scope.events.placable, $scope.events.modifiable);
@@ -727,7 +728,7 @@ Application.Controllers.controller('ReserveMachineController', ['$scope', '$tran
       angular.forEach(reservation.slots, function (s) {
         if (slot.start.isSame(s.start_at)) {
           slot.slot_id = s.id;
-          slot.user = user;
+          slot.users = [user];
         }
       });
       updateEvents(slot);
diff --git a/app/models/availability.rb b/app/models/availability.rb
index a794c9a50..e737c6d03 100644
--- a/app/models/availability.rb
+++ b/app/models/availability.rb
@@ -124,16 +124,16 @@ class Availability < ApplicationRecord
     end
   end
 
-  def available_places_per_slot
+  def available_places_per_slot(reservable = nil)
     case available_type
     when 'training'
-      nb_total_places || trainings.map(&:nb_total_places).max
+      nb_total_places || reservable&.nb_total_places || trainings.map(&:nb_total_places).max
     when 'event'
       event.nb_total_places
     when 'space'
-      nb_total_places || spaces.map(&:default_places).max
+      nb_total_places || reservable&.default_places || spaces.map(&:default_places).max
     when 'machines'
-      machines.count
+      reservable.nil? ? machines.count : 1
     else
       raise TypeError
     end
diff --git a/app/models/slot.rb b/app/models/slot.rb
index 38eb8d2b6..32334d2ba 100644
--- a/app/models/slot.rb
+++ b/app/models/slot.rb
@@ -12,8 +12,8 @@ class Slot < ApplicationRecord
 
   attr_accessor :is_reserved, :machine, :space, :title, :can_modify, :current_user_slots_reservations_ids
 
-  def full?
-    availability_places = availability.available_places_per_slot
+  def full?(reservable = nil)
+    availability_places = availability.available_places_per_slot(reservable)
     return false if availability_places.nil?
 
     slots_reservations.where(canceled_at: nil).count >= availability_places
diff --git a/app/views/api/availabilities/_slot.json.jbuilder b/app/views/api/availabilities/_slot.json.jbuilder
index 0f7730ed2..45635e41f 100644
--- a/app/views/api/availabilities/_slot.json.jbuilder
+++ b/app/views/api/availabilities/_slot.json.jbuilder
@@ -6,7 +6,7 @@ json.title slot.title
 json.start slot.start_at.iso8601
 json.end slot.end_at.iso8601
 json.is_reserved slot.is_reserved
-json.is_completed slot.full?
+json.is_completed slot.full?(reservable)
 json.backgroundColor 'white'
 
 json.availability_id slot.availability_id
diff --git a/app/views/api/availabilities/machine.json.jbuilder b/app/views/api/availabilities/machine.json.jbuilder
index 95646ba52..6296ee385 100644
--- a/app/views/api/availabilities/machine.json.jbuilder
+++ b/app/views/api/availabilities/machine.json.jbuilder
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 json.array!(@slots) do |slot|
-  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role
+  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role, reservable: @machine
   json.borderColor machines_slot_border_color(slot)
 
   json.machine do
diff --git a/app/views/api/availabilities/public.json.jbuilder b/app/views/api/availabilities/public.json.jbuilder
index 23c65b64f..c5ac42899 100644
--- a/app/views/api/availabilities/public.json.jbuilder
+++ b/app/views/api/availabilities/public.json.jbuilder
@@ -40,16 +40,17 @@ json.array!(@availabilities) do |availability|
     end
     json.is_reserved availability.is_reserved
     json.is_completed availability.full?
-    if availability.availability.available_type == 'machines'
+    case availability.availability.available_type
+    when 'machines'
       json.machine_ids availability.availability.machines.map(&:id)
       json.borderColor machines_slot_border_color(availability)
-    elsif availability.availability.available_type == 'space'
+    when 'space'
       json.space_id availability.availability.space.first.id
       json.borderColor space_slot_border_color(availability)
-    elsif availability.availability.available_type == 'training'
+    when 'training'
       json.training_id availability.availability.trainings.first.id
       json.borderColor trainings_events_border_color(availability)
-    elsif availability.availability.available_type == 'event'
+    when 'event'
       json.event_id availability.availability.event.id
       json.borderColor trainings_events_border_color(availability)
     else
diff --git a/app/views/api/availabilities/spaces.json.jbuilder b/app/views/api/availabilities/spaces.json.jbuilder
index 45cb23d0a..2200fb689 100644
--- a/app/views/api/availabilities/spaces.json.jbuilder
+++ b/app/views/api/availabilities/spaces.json.jbuilder
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 json.array!(@slots) do |slot|
-  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role
+  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role, reservable: @space
   json.is_completed slot.full?
   json.borderColor space_slot_border_color(slot)
 
diff --git a/app/views/api/availabilities/trainings.json.jbuilder b/app/views/api/availabilities/trainings.json.jbuilder
index 5fc9b27b9..b4efdce10 100644
--- a/app/views/api/availabilities/trainings.json.jbuilder
+++ b/app/views/api/availabilities/trainings.json.jbuilder
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 json.array!(@slots) do |slot|
-  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role
+  json.partial! 'api/availabilities/slot', slot: slot, operator_role: @operator_role, reservable: slot.availability.trainings.first
   json.borderColor trainings_events_border_color(slot.availability)
 
   json.is_completed slot.full?