diff --git a/models/workflow/workflow_mongo_accessor.go b/models/workflow/workflow_mongo_accessor.go
index b31f6b9..f8d2f50 100644
--- a/models/workflow/workflow_mongo_accessor.go
+++ b/models/workflow/workflow_mongo_accessor.go
@@ -2,6 +2,7 @@ package oclib
 
 import (
 	"errors"
+	"time"
 
 	"cloud.o-forge.io/core/oc-lib/dbs"
 	"cloud.o-forge.io/core/oc-lib/dbs/mongo"
@@ -10,6 +11,7 @@ import (
 	"cloud.o-forge.io/core/oc-lib/models/workflow_execution"
 	"cloud.o-forge.io/core/oc-lib/models/workspace"
 	"github.com/vk496/cron"
+	"go.mongodb.org/mongo-driver/bson/primitive"
 )
 
 type workflowMongoAccessor struct {
@@ -20,6 +22,67 @@ func New() *workflowMongoAccessor {
 	return &workflowMongoAccessor{}
 }
 
+func (wfa *workflowMongoAccessor) checkBooking(data *Workflow) bool {
+	accessor := (&workflow_execution.WorkflowExecution{}).GetAccessor()
+	s := data.Schedule.Start.Add(time.Duration(-10) * time.Second)
+	e := data.Schedule.Start.Add(time.Duration(10) * time.Second)
+	sd := primitive.NewDateTimeFromTime(s)
+	ed := primitive.NewDateTimeFromTime(e)
+	f := dbs.Filters{
+		And: map[string][]dbs.Filter{
+			"execution_date": {{Operator: "gte", Value: sd}, {Operator: "lte", Value: ed}},
+		},
+	}
+	arr, _, _ := accessor.Search(&f, "")
+	return len(arr) == 0
+}
+
+func (wfa *workflowMongoAccessor) getExecutions(id string, data *Workflow) ([]*workflow_execution.WorkflowExecution, error) {
+	workflows_execution := []*workflow_execution.WorkflowExecution{}
+	if data.Schedule != nil {
+		if data.Schedule.Start == nil || data.Schedule.Start.IsZero() {
+			return workflows_execution, errors.New("should get a start date on the scheduler.")
+		}
+		if data.Schedule.End != nil && data.Schedule.End.IsZero() {
+			data.Schedule.End = nil
+		}
+		if len(data.Schedule.Cron) > 0 {
+			if data.Schedule.End == nil {
+				return workflows_execution, errors.New("a cron task should got a end date.")
+			}
+			c, err := cron.Parse(data.Schedule.Cron)
+			if err != nil {
+				return workflows_execution, errors.New("Bad cron message: " + err.Error())
+			}
+			for s := c.Next(*data.Schedule.Start); !s.IsZero() && s.Before(*data.Schedule.End); s = c.Next(s) {
+				obj := &workflow_execution.WorkflowExecution{
+					AbstractObject: utils.AbstractObject{
+						Name: data.Schedule.Name,
+					},
+					ExecDate:   &s,
+					EndDate:    data.Schedule.End,
+					State:      1,
+					WorkflowID: id,
+				}
+				workflows_execution = append(workflows_execution, obj)
+			}
+
+		} else {
+			obj := &workflow_execution.WorkflowExecution{
+				AbstractObject: utils.AbstractObject{
+					Name: data.Schedule.Name,
+				},
+				ExecDate:   data.Schedule.Start,
+				EndDate:    data.Schedule.End,
+				State:      1,
+				WorkflowID: id,
+			}
+			workflows_execution = append(workflows_execution, obj)
+		}
+	}
+	return workflows_execution, nil
+}
+
 func (wfa *workflowMongoAccessor) DeleteOne(id string) (utils.DBObject, int, error) {
 	return wfa.GenericDeleteOne(id, wfa)
 }
@@ -33,53 +96,23 @@ func (wfa *workflowMongoAccessor) execution(id string, realData *Workflow, delet
 	if r.Schedule.Start == realData.Schedule.Start && r.Schedule.End == realData.Schedule.End && r.Schedule.Cron == realData.Schedule.Cron {
 		return 200, nil
 	}
+	if !wfa.checkBooking(realData) {
+		return 409, errors.New("the booking is already taken.")
+	}
 	if delete {
 		mongo.MONGOService.DeleteMultiple(map[string]interface{}{
 			"workflow_id": id,
 			"state":       1,
 		}, utils.WORKFLOW_EXECUTION.String())
 	}
-	if realData.Schedule != nil {
-		accessor := (&workflow_execution.WorkflowExecution{}).GetAccessor()
-		if realData.Schedule.Start == nil || realData.Schedule.Start.IsZero() {
-			return 422, errors.New("should get a start date on the scheduler.")
-		}
-		if realData.Schedule.End != nil && realData.Schedule.End.IsZero() {
-			realData.Schedule.End = nil
-		}
-		if len(realData.Schedule.Cron) > 0 {
-			if realData.Schedule.End == nil {
-				return 422, errors.New("a cron task should got a end date.")
-			}
-			c, err := cron.Parse(realData.Schedule.Cron)
-			if err != nil {
-				return 422, errors.New("Bad cron message: " + err.Error())
-			}
-			for s := c.Next(*realData.Schedule.Start); !s.IsZero() && s.Before(*realData.Schedule.End); s = c.Next(s) {
-				obj := &workflow_execution.WorkflowExecution{
-					AbstractObject: utils.AbstractObject{
-						Name: realData.Schedule.Name,
-					},
-					ExecDate:   &s,
-					EndDate:    realData.Schedule.End,
-					State:      1,
-					WorkflowID: id,
-				}
-				accessor.StoreOne(obj)
-			}
-
-		} else {
-			obj := &workflow_execution.WorkflowExecution{
-				AbstractObject: utils.AbstractObject{
-					Name: realData.Schedule.Name,
-				},
-				ExecDate:   realData.Schedule.Start,
-				EndDate:    realData.Schedule.End,
-				State:      1,
-				WorkflowID: id,
-			}
+	accessor := (&workflow_execution.WorkflowExecution{}).GetAccessor()
+	execs, err := wfa.getExecutions(id, realData)
+	if err != nil && len(execs) > 0 {
+		for _, obj := range execs {
 			accessor.StoreOne(obj)
 		}
+	} else {
+		return 422, err
 	}
 	return 200, nil
 }
diff --git a/models/workflow_execution/workflow_execution_mongo_accessor.go b/models/workflow_execution/workflow_execution_mongo_accessor.go
index 0c83095..5d905d7 100644
--- a/models/workflow_execution/workflow_execution_mongo_accessor.go
+++ b/models/workflow_execution/workflow_execution_mongo_accessor.go
@@ -72,7 +72,6 @@ func (wfa *workflowExecutionMongoAccessor) Search(filters *dbs.Filters, search s
 		wfa.Logger.Error().Msg("Could not store to db. Error: " + err.Error())
 		return nil, code, err
 	}
-
 	var results []WorkflowExecution
 	if err = res_mongo.All(mongo.MngoCtx, &results); err != nil {
 		return nil, 404, err