Delegate access can only be granted in Outlook (not Outlook Web Access).

Allow another user to access your mailbox folders (Outlook 2010/2007)

Using Office 2007, click Tools (top menu) then select Options and click the Delegates tab (in the Options box).

Using Office 2010, click File, click the Account Settings button and select Delegate Access

Then follow these instructions:

1. Click Add, select the user you want to assign delegate access to, click Add, and then click OK.
2. For each folder you want the delegate to access (eg, Inbox, Calendar, Contacts), set the user's permissions on that folder from the options given:
1. Reviewer: can only read items.
2. Author: can create and read all items but cannot edit or delete.
3. Editor: can create, read, edit, and delete all items.
   Tip: to be able to arrange meetings for you, the delegate must have editor priveleges on your Calendar folder.
   To be able to send, reply or forward mail for you, the delegate must have Editor or Author priveleges on the mailbox.
3. If you want Outlook to send a message to the delegate outlining these permissions, tick the Automatically send a message to delegate summarizing these permissions check box.
4. If you want the delegate to see any items that you have marked as private, tick the Delegate can see my private items check box.
5. Click OK to return to the Options dialog box
6. You have the option to send meeting requests and responses only to my delegate by selecting the delegate's name and ticking the checkbox below.
7. Click OK to finish.

Access the mailbox folders of another person (that has granted you access) (Outlook 2007)

1. Click Tools, then Account Settings.
2. Click your Exchange Server account and then click Change.
3. Click More Settings to open the Microsoft Exchange dialog box.
4. Click the Advanced tab, then click Add to open the Add Mailbox dialog box.
5. Type the owner's name and click OK.
6. Click OK to return to the Change E-mail Account dialog box. Click Next.
7. Click Finish to return to the Account Settings dialog box.
8. Click Close. Outlook displays both sets of mail folders.

Send a message from the mailbox of another person (Outlook 2007)

1. Start a new message or reply to or forward an existing message in one of the owner's message folders.
2. Make sure the From field is displayed by choosing Options, Show From.
3. Type the owner's name into the From field, and then fill out and send the message normally.
4. When the recipient receives the message, the From field data has the following format: Delegate Name on behalf of Owner Name.