You don't. The list is built into Outlook and cannot be changed. It is also not possible to create a custom drop-down list in a folder view.
--
Sue Mosher, Outlook MVP
Author of Microsoft Outlook 2007 Programming:
Jumpstart for Power Users and Administrators
http://www.outlookcode.com/article.aspx?id=54
"DerekV" <(E-Mail Removed)> wrote in message news:4AC48098-5C8F-45D0-ACD2-(E-Mail Removed)...
> In Outlook there is a column called Status,
> You enter text in Status by a Pop-up or Drop-down list.
>
> How do you edit or change this list