If your practice operates more than one HMRC Agent Services Account, each with its own Agent Reference Number (ARN), Dext Solo lets you connect all of them and assign the correct ARN to each client, instead of consolidating onto a single agent account. This article covers adding, connecting, and assigning multiple ARNs. If your practice only uses one ARN, there's nothing you need to do — your existing setup carries on as before.
Before you start
Before you can add another ARN, your practice needs a Solo licence, an existing HMRC connection, and a user with Practice Admin access — only Practice Admins can add or connect an ARN. If your practice hasn't connected to HMRC yet, go tо How to connect Dext to HMRC for MTD for Income Tax first.
Add and connect another ARN
To add another ARN, go to Practice settings > Practice profile > HMRC connection and select Manage HMRC ARNs:
Select Add ARN.
Enter a name for the agent account (for example, the office or firm it relates to) and its agent reference number.
Select Connect. You'll be redirected to HMRC's website to verify the agent account.
Complete the verification steps on HMRC's website. Dext redirects you back automatically to the MTD for IT obligations dashboard, where a banner confirms the new ARN is connected.
Set the default ARN
One ARN is always marked as the practice Default. Dext assigns every new client to the default ARN automatically, so no client is left without an agent account. To use a different ARN as the default, select it from the dropdown in the Manage HMRC ARNs list. You can still reassign individual clients to a different ARN afterwards.
Disconnect an ARN
To disconnect an ARN your practice no longer needs, go to Practice settings > Practice profile > HMRC connection > Manage HMRC ARNs and select Disconnect next to it.
Note: Disconnecting an ARN revokes the HMRC authorisation and removes it from your practice — this can't be undone. The default ARN can't be disconnected directly; set a different ARN as the default first.
Assign an ARN to an individual client
To choose which ARN a specific client's MTD submissions go out under, open the client account and go to Business settings > Connections > HMRC connection. Choose the ARN from the HMRC ARN dropdown.
Note: This dropdown only appears once your practice has connected more than one ARN. Leaving it set to Use practice default means the client always follows whichever ARN is marked as default, even if you change the default later.
Assign ARNs to multiple clients at once
If you're reassigning several clients or setting up ARNs for the first time across your client base, you can bulk-assign from the clients list instead of updating clients individually.
To bulk-assign an ARN:
Go to Clients and select the cog icon to open Columns to display. Under Additional columns, select HMRC ARN, then select Apply.
Select the filter icon and filter by Products: Solo and Client type: Individual to narrow the list to your Solo clients, then select Apply.
Select the checkboxes next to the clients you want to reassign, then select Bulk edit.
In the HMRC ARN dropdown, choose the ARN to assign, then select Confirm.
Note: The HMRC ARN column and bulk-edit option are only available once your practice has connected more than one ARN.
Track ARNs on the MTD IT obligations dashboard
Every obligation on the MTD IT obligations dashboard shows which ARN it's submitted under, so you can see at a glance how work is spread across your connected agent accounts. For the full breakdown of dashboard columns and filters, go tо Using the MTD IT obligations dashboard.