Issue/Question
- How do I send mail as another user in Outlook?
Explanation
A "delegate" is someone who has been delegated access to another person's mail folders or calendar. Depending on how delegation is configured, the delegate may receive copies of calendar invites, be able to accept or decline invites on behalf of the other person, and/or be able to send or reply "on behalf of" the other person. When mail is sent "on behalf of", the recipient will see both the primary person's mailbox name as well as the delegate's name in the "From" line. Delegation is setup in Outlook by the mailbox owner.
To "send as" another person or mailbox requires permissions on the mailbox set by an Exchange administrator. When you "send as" the message appears to come from the other person or mailbox. Permission to "send as" can be granted without full mailbox access.
Full mailbox access allows a user to open another mailbox, but does not grant "send as". The "send as" and "full mailbox access" permissions can be granted separately or together. Both are set by an Exchange administrator.
Resolution
Delegate and "Send on Behalf of" Access
To grant access to a delegate, see: Allow someone else to manage your mail and calendar (external link)
To manage another person's mail or calendar, see: Manage another person's mail and calendar items (external link)
"Send As" Access
To "send as" another person or mailbox, see: Change the account used to send email messages (external link)
Note that to "send as" another person or mailbox, an Exchange administrator must first grant you access to do so. Even if you have full access to open a mailbox, you might not have "send as" rights.