You can retract appointments, tasks, and notes after the recipients have opened them, unlike regular email messages. When you retract an appointment, task, or note, it is removed from the recipients' calendars and mailboxes.
To retract an appointment, task, or note, follow these steps:
Open your Sent Items folder and highlight the message to be retracted.
Press the Delete key (or right-click the message and select Delete).
Select Recipient's Mailbox or All Mailboxes and then click OK.
Here's how to reschedule or resend a calendar entry:
Right-click the message in the Sent Items folder and select Resend.
Change the message information, if necessary, and click Send.
If you want to retract the original entry, choose Yes when prompted.
Because the recipients receive no warning (the item simply disappears from their calendars), it is good messaging etiquette to let them know you have retracted the item.
The ability to retract items you send allows you to take back or edit these items.