Allow Clients to Send Mail
Tip To allow a user to act as a delegate for another user, you must allow a user (delegate) to have access to another user's mailbox. To accomplish this you must create both user accounts on the delegate's IMAP client. The user who is allowing access to their mailbox must set appropriate ACLs on the folders that they want the delegate user to see. The delegate user logs in to another user's mailbox using the following format: domain\delegate\mailbox where domain\delegate is the Windows account name of the delegate and the mailbox is the mailbox being shared.