diff --git a/controllers/auth.ts b/controllers/auth.ts
index 07d1476..666b2e7 100644
--- a/controllers/auth.ts
+++ b/controllers/auth.ts
@@ -4,6 +4,7 @@ import { NextFunction, Request, Response } from 'express';
 import logger from '../utils/logger';
 import * as authService from '../services/authService';
 import { apiResponse } from '../@types/apiReponse';
+import { MicrosoftOAuthJson } from '../@types/providers';
 
 /**
  * Makes authentication call to google statergy
@@ -87,27 +88,33 @@ const microsoftAuthCallback = (
   const rCalUiUrl = new URL(config.get('services.rCalUi.baseUrl'));
 
   try {
-    return passport.authenticate('microsoft', {}, async (err, _, user) => {
-      if (err) {
-        logger.error(err);
-        return res.boom(Boom.unauthorized('User cannot be authenticated'));
+    return passport.authenticate(
+      'microsoft',
+      {},
+      async (err: any, _: any, user: { _json: MicrosoftOAuthJson }) => {
+        if (err) {
+          logger.error(err);
+          return res.boom(Boom.unauthorized('User cannot be authenticated'));
+        }
+        const userData = await authService.loginOrSignupWithMicrosoft(
+          user._json
+        );
+        const token = authService.generateAuthToken({ userId: userData?.id });
+
+        // respond with a cookie
+        res.cookie(config.get('userAccessToken.cookieName'), token, {
+          domain: rCalUiUrl.hostname,
+          expires: new Date(
+            Date.now() + config.get('userAccessToken.ttl') * 1000
+          ),
+          httpOnly: true,
+          secure: true,
+          sameSite: 'lax',
+        });
+
+        return res.redirect(rCalUiUrl.href);
       }
-      const userData = await authService.loginOrSignupWithMicrosoft(user._json);
-      const token = authService.generateAuthToken({ userId: userData?.id });
-
-      // respond with a cookie
-      res.cookie(config.get('userAccessToken.cookieName'), token, {
-        domain: rCalUiUrl.hostname,
-        expires: new Date(
-          Date.now() + config.get('userAccessToken.ttl') * 1000
-        ),
-        httpOnly: true,
-        secure: true,
-        sameSite: 'lax',
-      });
-
-      return res.redirect(rCalUiUrl.href);
-    })(req, res, next);
+    )(req, res, next);
   } catch (err: any) {
     logger.error(err);
 
diff --git a/controllers/events.ts b/controllers/events.ts
index 71da9f1..3636ff0 100644
--- a/controllers/events.ts
+++ b/controllers/events.ts
@@ -1,8 +1,10 @@
+import { z } from 'zod';
 import { Event, EventType } from '@prisma/client';
 import { Request, Response } from 'express';
 import Boom from '@hapi/boom';
 import prisma from '../prisma/prisma';
 import { findEvent, findEventFromCalendar } from '../services/eventsService';
+import { getAcknowledgementSchema } from '../middlewares/validators/zod-schemas/events';
 
 /**
  * Route used to post event
@@ -99,7 +101,10 @@ const getEvents = async (req: Request, res: Response): Promise<any> => {
  * @param req {Object} - Express request object
  * @param res {Object} - Express response object
  */
-const getCalendarEvents = async (req: Request, res: Response): Promise<any> => {
+const getCalendarEvents = async (
+  req: Request,
+  res: Response
+): Promise<Response> => {
   try {
     const { calendarId } = req.params;
     const { startTime, endTime } = req.query;
@@ -120,4 +125,40 @@ const getCalendarEvents = async (req: Request, res: Response): Promise<any> => {
   }
 };
 
-export { postEvent, getEvents, getCalendarEvents };
+type TAcknowledgementStatusReq = z.infer<typeof getAcknowledgementSchema>;
+
+const getAcknowledgementStatus = async (
+  req: Request,
+  res: Response
+): Promise<Response> => {
+  const { eventId, attendeeId } = req.params;
+  const { status } = req.body as TAcknowledgementStatusReq['body'];
+
+  const attendeeData = await prisma.attendees.findFirst({
+    where: {
+      eventId: Number(eventId),
+      attendeeId: Number(attendeeId),
+    },
+  });
+
+  if (attendeeData === null) {
+    return res.boom(Boom.badRequest('Attendee not found'));
+  }
+
+  const updatedData = await prisma.attendees.update({
+    where: {
+      id: attendeeData.id,
+    },
+    data: {
+      acknowledgement: status,
+    },
+  });
+
+  if (updatedData.acknowledgement === status) {
+    return res.json({ message: 'Acknowledgement status updated' });
+  } else {
+    return res.boom(Boom.internal('Something went wrong'));
+  }
+};
+
+export { postEvent, getEvents, getCalendarEvents, getAcknowledgementStatus };
diff --git a/middlewares/validators/zod-schemas/events.ts b/middlewares/validators/zod-schemas/events.ts
index 8460cac..795f101 100644
--- a/middlewares/validators/zod-schemas/events.ts
+++ b/middlewares/validators/zod-schemas/events.ts
@@ -1,4 +1,5 @@
 import { z } from 'zod';
+import { EventAcknowledgements } from '@prisma/client';
 
 const EVENT_TYPE = ['event'] as const;
 
@@ -24,6 +25,22 @@ const getEventSchema = z.object({
   }),
 });
 
+const UPDATED_ACKNOWLEDGEMENT_TYPES = [
+  EventAcknowledgements.ACCEPTED,
+  EventAcknowledgements.DECLINED,
+  EventAcknowledgements.TENTATIVE,
+] as const;
+
+const getAcknowledgementSchema = z.object({
+  params: z.object({
+    eventId: z.preprocess((a) => Number(a), z.number().positive()),
+    attendeeId: z.preprocess((a) => Number(a), z.number().positive()),
+  }),
+  body: z.object({
+    status: z.enum(UPDATED_ACKNOWLEDGEMENT_TYPES),
+  }),
+});
+
 const getCalenderEventSchema = z.object({
   params: z.object({
     calendarId: z.preprocess((a) => Number(a), z.number().positive()),
@@ -34,4 +51,9 @@ const getCalenderEventSchema = z.object({
   }),
 });
 
-export { postEventSchema, getEventSchema, getCalenderEventSchema };
+export {
+  postEventSchema,
+  getEventSchema,
+  getCalenderEventSchema,
+  getAcknowledgementSchema,
+};
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 40b48e0..46fbf7d 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -95,12 +95,20 @@ enum RecurringFrequency {
   HOURLY
 }
 
+enum EventAcknowledgements {
+  AWAITING
+  ACCEPTED
+  DECLINED
+  TENTATIVE
+}
+
 model Attendees {
-  id         Int   @id @default(autoincrement())
-  eventId    Int
-  event      Event @relation(fields: [eventId], references: [id])
-  attendeeId Int
-  attendee   Users @relation(fields: [attendeeId], references: [id])
+  id              Int                   @id @default(autoincrement())
+  eventId         Int
+  event           Event                 @relation(fields: [eventId], references: [id])
+  attendeeId      Int
+  attendee        Users                 @relation(fields: [attendeeId], references: [id])
+  acknowledgement EventAcknowledgements @default(AWAITING)
 }
 
 enum CalendarType {
diff --git a/routes/events.ts b/routes/events.ts
index 779bac8..efc59f9 100644
--- a/routes/events.ts
+++ b/routes/events.ts
@@ -1,8 +1,14 @@
 import { Router } from 'express';
-import { getCalendarEvents, getEvents, postEvent } from '../controllers/events';
+import {
+  getAcknowledgementStatus,
+  getCalendarEvents,
+  getEvents,
+  postEvent,
+} from '../controllers/events';
 import authenticate from '../middlewares/authenticate';
 import { validate } from '../middlewares/validators/validator';
 import {
+  getAcknowledgementSchema,
   getCalenderEventSchema,
   getEventSchema,
   postEventSchema,
@@ -13,6 +19,14 @@ const router = Router();
 /* eslint-disable @typescript-eslint/no-misused-promises */
 router.post('/', authenticate, validate(postEventSchema), postEvent);
 router.get('/:eventId', authenticate, validate(getEventSchema), getEvents);
+
+router.patch(
+  '/:eventId/attendee/:attendeeId',
+  // authenticate,
+  validate(getAcknowledgementSchema),
+  getAcknowledgementStatus
+);
+
 router.get(
   '/calendar/:calendarId',
   authenticate,