How to grant permission for a user to 'Send on behalf' option on Microsoft Exchange Server 2007/2010

Sometimes, there is a need to send a message on behalf of a user who is out of office or inaccessible. You can easily set up this option for each user on Microsoft Exchange. In order to do so:

1. Open Exchange Management Console (Start, Programs, Microsoft Exchange Server 2010).
2. In the left pane, expand the Recipient Configuration tree.
3. Click Mailbox.
4. In the middle pane double click the user you want to be able to send on behalf of.
5. Go to the Mail Flow Settings tab.
6. On the list highlight the Delivery options and click the Properties button.
7. In the new window you can use the Add button to add the user you want to grant permissions to write on behalf of the edited account (Fig.1.).

Fig.1. A window where you can add users to send messages on behalf of.

8. Confirm changes with the OK button on all windows.

Now, the user who has been granted permissions to write on behalf of can use the feature. In the from field of the message there will be a notice included e.g. "User A On Behalf Of User B." 

You can read how to send messages on behalf of another user in MS Outlook 2010 in the article titled: How to write an e-mail message as a delegate with 'Send on behalf' permission in MS Outlook 2010.