How can I reject an email

[Roon Wheel]

I am trying to find out if there is a way to reject an incoming email and the
sender of the email knowing the email was rejected.

 

[K. Orland]

Create a rule that replies with a message, kind of like an out of office
response. However if you don't connect to an Exchange server, then you have
to leave Outlook running all the time.

http://www.howto-outlook.com/faq/oooa.htm