---
title: How to Add Account Delegates to Office 365 Resource Mailboxes (the easy way to add Exchange Delegates)
slug: how-to-add-account-delegates-to-office-365-resource-mailboxes
excerpt: Sometimes it can be useful to create a Service Account that can access all of the resource mailboxes, so that you can easily control third-party access to your tenant via a single set of credentials.
published: 2019-05-03T00:03:00.000Z
updated: 2026-04-11T02:37:00.000Z
feature_image: /blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/colleagues-talking-in-open-plan-office.1080.webp
feature_image_alt: Colleagues talking at desks in an open plan office
tags: [office-365, exchange, delegated-access, delegates, azure-ad]
author: James Futhey
author_slug: james-2
meta_description: Sometimes it can be useful to create a Service Account that can access all of the resource mailboxes, so that you can easily control third-party access to..
status: published
---

For some services, such as ours, it can be useful to create a **Service Account** that can access all of the resource mailboxes in your company, so that you can easily control third-party access to your tenant via a single set of credentials. Not to mention, this also simplifies the setup and provisioning process.

This has always been an option for Office 365 and Exchange users via EMC and PowerShell. But recently, the Office 365 Admin portal has quietly added the feature as well. Meaning, you can enable delegated access and create a service account in just a few clicks.

<iframe class="video-embed is-portrait" style="aspect-ratio: 720 / 1080" src="https://www.youtube.com/embed/YkagZHkSmc0" title="How to Add Delegates to an account in Office 365" loading="lazy" allowfullscreen></iframe>

### 1\. Log into the Office 365 Admin Portal & Select Rooms and Equipment from the Left Menu

First, you’ll want to log into the Office 365 Admin Portal, located at [**https://portal.office.com/**](https://portal.office.com/) (select Admin). You will need to be an Office 365 Administrator to complete this step.

![Microsoft 365 admin center with the Resources menu open on Rooms and equipment](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-admin-rooms-and-equipment-menu.1440.webp)

### 2\. Select your Resource Mailbox

This is the mailbox which will be accessed via your service account.

![Microsoft 365 admin center rooms list with a room mailbox selected](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-admin-select-room-mailbox.1440.webp)

### 3\. Select Edit to edit your list of Delegates

![Room mailbox panel with the Edit action beside the Delegates row highlighted](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-room-delegates-edit.1440.webp)

### 4\. Click ‘Add Delegate’, and add your service account as a delegate

Then click ‘Save’ to confirm.

![Add delegates panel with a search box for finding users to add](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-add-delegates-panel.800.webp)

![Delegate picker listing organisation users with one selected to add](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-delegate-picker-user-list.800.webp)

![Delegate picker with the chosen user selected and the Save button highlighted](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-delegate-picker-save.800.webp)

Once you confirm your list of delegates, which should include your service account, you can close this pane.

![Confirmation message reading Room Mailbox was updated](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-room-mailbox-updated-confirmation.1200.webp)

![Room mailbox delegates list showing two delegates assigned](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-room-delegates-list.1200.webp)

### 5\. Confirm your service account as a delegate

![Room mailbox summary confirming two delegates are assigned to the resource](/blog/images/how-to-add-account-delegates-to-office-365-resource-mailboxes/m365-room-delegates-confirmed.1440.webp)

### That’s it!

You’ll need to repeat this process for each Office 365 Resource Mailbox you want to access via a Service User.