Custom "From" field

[JTechmeier@xxxxxxxxxxxxxx]

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I think this was covered previously, but I can't find it in the
archives...

How do you change who a message is sent from? Our marketing department
would like to send out promotional emails to customers, but want to show
the regional CSR as the sender. Location documents keep popping in my head
but I can't find anything to back it up.

Any help would be appreciated.

As a side note, would this work for hosting multiple domains? (ie. John
Doe (jdoe@acme.com) sends a message that appears to come from Mike Smith
(msmith@abc.com))

John Techmeier
IT Director
The Medalcraft Mint, Inc.
Email:  jtechmeier@medalcraft.com