diff --git a/ensalador.js b/ensalador.js
index a65c0cc8b2ce757c84251c7ef95c203af2647a1c..daee89a8b8a006836a958439600ce1d760c36056 100644
--- a/ensalador.js
+++ b/ensalador.js
@@ -162,6 +162,8 @@ class Schedule{
       "log": this.log,
       "lat": this.lat
     };
+    if (! obj.assigned )
+      delete obj.assigned
 
     // Remove undefined props (usefull when transform into YAML)
     Object.keys(obj).forEach(key => {
@@ -185,7 +187,7 @@ class ScheduleCollection{
 
   toJSON(){
     return {
-      "schedules": this.schedules.map(schedule => {return schedule.toJSON()}),
+      "schedules": this.schedules.map(schedule => { return schedule? schedule.toJSON() : "{}"}),
       "id": this.id
     }
   }
@@ -384,4 +386,4 @@ module.exports = {Ensalador, EnsaladorPart, Schedule, ScheduleCollection, Room,
 
 // e.execute((err,schedules) => {
 //   console.log(err,schedules);
-// })
\ No newline at end of file
+// })