Remove an alias from the admin / owner's email address

Remove the address through the Exchange admin center, then add it to the employee’s mailbox after it no longer appears on your mailbox.

Remove the alias

1. Open the Exchange admin center.
2. Go to Recipients → Mailboxes.
3. Select your mailbox.
4. Go to General → Email addresses.
5. Select Manage email address types.
6. Select the alias, choose Remove, and then select Save. ^1^

This is an alternate route to the Microsoft 365 admin center’s Users → Active users → user → Manage email aliases page where the wastebasket normally appears. ^2^

Assign it to the employee

After saving the removal:

1. In the Exchange admin center, remain under Recipients → Mailboxes.
2. Select the employee’s mailbox.
3. Go to General → Email addresses → Manage email address types.
4. Select Add email address type → SMTP.
5. Enter the released address and select OK → Save.

An address can belong to only one mail-enabled object at a time. Moving it changes where new messages are delivered; messages previously received through that alias remain in your mailbox. ^3^

If the Remove control is still unavailable

Check these conditions:

• The address is primary: In the email-address list, the default reply address is shown in bold. Set another appropriate address as primary before trying to remove the old address. Do not remove or change your primary address unless the replacement is correct.
• Insufficient role: Alias management requires an Exchange-based administrative role, such as Exchange Administrator; being assigned another admin role does not necessarily grant recipient-management permission. ^4^
• Directory-synchronized user: If the page says the user is synchronized with local Active Directory, edit the user in Active Directory Users and Computers → Properties → Attribute Editor → proxyAddresses, remove the lowercase smtp:[Email] entry, and let Microsoft Entra Connect synchronize the change. The cloud interface is not authoritative for that condition. ^4^

PowerShell fallback

For a cloud-managed Exchange Online mailbox, connect to Exchange Online PowerShell and run:

$oldMailbox = "[Email]"
$newMailbox = "[Email]"
$address    = "[Email]"

Set-Mailbox $oldMailbox -EmailAddresses @{remove=$address}
Set-Mailbox $newMailbox -EmailAddresses @{add=$address}

The EmailAddresses property is multivalued, and Microsoft documents the @{remove=...} and @{add=...} syntax for moving individual addresses without replacing the mailbox’s other addresses. ^1^

If adding it to the employee reports that the address is still in use, locate the object retaining it:

Get-EXORecipient -ResultSize Unlimited |
    Where-Object {$_.EmailAddresses -match "[Email]"} |
    Format-List Name,RecipientType,EmailAddresses

Remove the address from the returned mailbox, group, contact, or other mail-enabled object before assigning it again. ^5^

References

1. Add or remove email addresses for a mailbox in Exchange Online
2. Troubleshoot: Remove an email alias from a user
3. Moving an alias from one Outlook account to another - consequences - Microsoft Q&A
4. Add another email alias for a Microsoft 365 business subscription user
5. Proxy address conflict when adding an email address in Exchange Online