diff --git a/src/controllers/03-employee-controller.ts b/src/controllers/03-employee-controller.ts
index 03ab1cc..95addd7 100644
--- a/src/controllers/03-employee-controller.ts
+++ b/src/controllers/03-employee-controller.ts
@@ -74,7 +74,7 @@ type EmployeeCreate = {
   dateOfBirth?: Date | null;
   gender: string;
   nationality: string;
-  otherNationality?: string;
+  otherNationality?: string | null;
 
   namePrefix?: string | null;
   firstName?: string;
@@ -111,7 +111,7 @@ type EmployeeUpdate = {
   dateOfBirth?: Date;
   gender?: string;
   nationality?: string;
-  otherNationality?: string;
+  otherNationality?: string | null;
 
   namePrefix?: string | null;
   firstName?: string;
diff --git a/src/controllers/03-employee-passport-controller.ts b/src/controllers/03-employee-passport-controller.ts
index 5509373..12e0b01 100644
--- a/src/controllers/03-employee-passport-controller.ts
+++ b/src/controllers/03-employee-passport-controller.ts
@@ -43,7 +43,7 @@ type EmployeePassportPayload = {
 
   workerStatus: string;
   nationality: string;
-  otherNationality: string;
+  otherNationality?: string;
   namePrefix?: string | null;
   firstName: string;
   firstNameEN: string;
diff --git a/src/controllers/05-quotation-controller.ts b/src/controllers/05-quotation-controller.ts
index 9fddd04..7d27e2e 100644
--- a/src/controllers/05-quotation-controller.ts
+++ b/src/controllers/05-quotation-controller.ts
@@ -55,7 +55,7 @@ type QuotationCreate = {
         dateOfBirth: Date;
         gender: string;
         nationality: string;
-        otherNationality?: string;
+        otherNationality?: string | null;
         namePrefix?: string;
         firstName: string;
         firstNameEN: string;
@@ -113,7 +113,7 @@ type QuotationUpdate = {
         dateOfBirth: Date;
         gender: string;
         nationality: string;
-        otherNationality?: string;
+        otherNationality?: string | null;
 
         namePrefix?: string;
         firstName?: string;
@@ -1010,7 +1010,7 @@ export class QuotationActionController extends Controller {
             dateOfBirth: Date;
             gender: string;
             nationality: string;
-            otherNationality?: string;
+            otherNationality?: string | null;
             namePrefix?: string;
             firstName: string;
             firstNameEN: string;
@@ -1033,7 +1033,7 @@ export class QuotationActionController extends Controller {
           dateOfBirth: Date;
           gender: string;
           nationality: string;
-          otherNationality?: string;
+          otherNationality?: string | null;
           namePrefix?: string;
           firstName: string;
           firstNameEN: string;
diff --git a/src/controllers/09-debit-note-controller.ts b/src/controllers/09-debit-note-controller.ts
index 118575b..9c247be 100644
--- a/src/controllers/09-debit-note-controller.ts
+++ b/src/controllers/09-debit-note-controller.ts
@@ -76,7 +76,7 @@ type DebitNoteCreate = {
         dateOfBirth: Date;
         gender: string;
         nationality: string;
-        otherNationality: string;
+        otherNationality?: string | null;
         namePrefix?: string;
         firstName: string;
         firstNameEN: string;
@@ -112,7 +112,7 @@ type DebitNoteUpdate = {
         dateOfBirth: Date;
         gender: string;
         nationality: string;
-        otherNationality: string;
+        otherNationality?: string | null;
         namePrefix?: string;
         firstName?: string;
         firstNameEN: string;