diff --git a/internal/domain/main-entities/chemo-plan/dto.go b/internal/domain/main-entities/chemo-plan/dto.go
index d83af082..1e8d4bb9 100644
--- a/internal/domain/main-entities/chemo-plan/dto.go
+++ b/internal/domain/main-entities/chemo-plan/dto.go
@@ -50,6 +50,10 @@ type FailDto struct {
 	Id      uint    `json:"id"`
 	Reasons *string `json:"reason"`
 }
+type FailReason struct {
+	Date       *time.Time `json:"date"`
+	FailReason *string    `json:"failReason"`
+}
 
 type MetaDto struct {
 	PageNumber int `json:"page_number"`
diff --git a/internal/use-case/main-use-case/chemo-plan/case.go b/internal/use-case/main-use-case/chemo-plan/case.go
index 99ef3a63..6a4c426e 100644
--- a/internal/use-case/main-use-case/chemo-plan/case.go
+++ b/internal/use-case/main-use-case/chemo-plan/case.go
@@ -253,4 +253,44 @@ func Delete(input e.DeleteDto) (*d.Data, error) {
 
 }
 
-func Fail(i)
+func Fail(input e.FailDto) (*d.Data, error) {
+	rdDto := e.ReadDetailDto{Id: input.Id}
+	var data *e.ChemoPlan
+	var err error
+
+	event := pl.Event{
+		Feature: "Chemo-Fail",
+		Source:  source,
+	}
+
+	// Start log
+	pl.SetLogInfo(&event, input, "started", "update")
+
+	err = dg.I.Transaction(func(tx *gorm.DB) error {
+		pl.SetLogInfo(&event, rdDto, "started", "DBReadDetail")
+		if data, err = ReadDetailData(rdDto, &event, tx); err != nil {
+			return err
+		}
+
+		if err := UpdateData(data, &event, tx); err != nil {
+			return err
+		}
+
+		pl.SetLogInfo(&event, nil, "complete")
+		return nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &d.Data{
+		Meta: d.IS{
+			"source":    source,
+			"structure": "single-data",
+			"status":    "updated",
+		},
+		Data: data.ToResponse(),
+	}, nil
+
+}
diff --git a/internal/use-case/main-use-case/chemo-plan/helper.go b/internal/use-case/main-use-case/chemo-plan/helper.go
index dedacfd8..f1b6179d 100644
--- a/internal/use-case/main-use-case/chemo-plan/helper.go
+++ b/internal/use-case/main-use-case/chemo-plan/helper.go
@@ -5,6 +5,7 @@ Any functions that are used internally by the use-case
 package chemo_plan
 
 import (
+	"encoding/json"
 	e "simrs-vx/internal/domain/main-entities/chemo-plan"
 	ep "simrs-vx/internal/domain/main-entities/chemo-protocol"
 	ere "simrs-vx/internal/domain/references/encounter"
@@ -34,3 +35,12 @@ func setDataUpdate(data *e.ChemoPlan) {
 	status := ere.SPCComplete
 	data.Status = status
 }
+
+func setDatafail(input e.FailDto, data *e.ChemoPlan) {
+	data.RealizationDate = nil
+	data.Status = ere.SPCSchedule
+
+	var reasons []e.FailReason
+
+	_ := json.Unmarshal(data.Re)
+}
diff --git a/internal/use-case/main-use-case/chemo-plan/lib.go b/internal/use-case/main-use-case/chemo-plan/lib.go
index b90430cd..92d7c8eb 100644
--- a/internal/use-case/main-use-case/chemo-plan/lib.go
+++ b/internal/use-case/main-use-case/chemo-plan/lib.go
@@ -145,3 +145,28 @@ func DeleteData(data *e.ChemoPlan, event *pl.Event, dbx ...*gorm.DB) error {
 	pl.SetLogInfo(event, nil, "complete")
 	return nil
 }
+
+func UpdateFailData(input e.FailDto, data *e.ChemoPlan, event *pl.Event, dbx ...*gorm.DB) error {
+	pl.SetLogInfo(event, data, "started", "DBUpdate")
+	setDataUpdate(data)
+
+	var tx *gorm.DB
+	if len(dbx) > 0 {
+		tx = dbx[0]
+	} else {
+		tx = dg.I
+	}
+
+	if err := tx.Save(&data).Error; err != nil {
+		event.Status = "failed"
+		event.ErrInfo = pl.ErrorInfo{
+			Code:   "data-update-fail",
+			Detail: "Database update failed",
+			Raw:    err,
+		}
+		return pl.SetLogError(event, data)
+	}
+
+	pl.SetLogInfo(event, nil, "complete")
+	return nil
+}