You can use the "From" field for that when addressing an e-mail.
If it's not visible use View-> From Field
--
Robert Sparnaaij [MVP-Outlook]
www.howto-outlook.com
Tips of the month:
-Navigation Pane Tips & Tricks
-Create an Office 2003 CD slipstreamed with Service Pack 1
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"zhenzhu_jiang" <(E-Mail Removed)> wrote in message
news:29cb01c47e02$74259170$(E-Mail Removed)...
> Dear sir,
> I'm working with EXCHANGE 5.5/outlook 2000, my manager
> delegate his inbox to me, how can I send mail on behalf
> of him?
>
> Thank your prompt response!