I need to delete all emails with a specific agency name. The agency changed their name.

Dear Christine,

You don't need to delete your old emails. The old address usually comes from Outlook's AutoComplete list, a saved contact, or your organization's address book. Deleting messages won't change any of these. The quickest fix is to remove the old suggestion. Start typing the person's name in the To field, hover over the old address in the suggestion list, and select the X next to it. The next time you send to the new address, Outlook will suggest that one instead.

If the old address still appears, check whether it's saved in a contact:

1. Open People in Outlook and search for the person.
2. Open the contact and replace the old address with the new one.
3. Save the contact.

If the old address shows under Global Address List or Offline Global Address List, it comes from your organization's directory, and only your Microsoft 365 administrator can update it. After they update it, you can refresh the address book in classic Outlook with Send / Receive > Send/Receive Groups > Download Address Book.

If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

If you remove a suggestion and it keeps coming back, this may be related to a known issue: In AutoComplete, the "X" to remove individual suggested recipients might not work as expected

I hope this information is helpful and provide you with a clear path forward. Should you have any further questions or need additional assistance, please don't hesitate to reach out. I'm always happy to help. Have a wonderful day! 

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