As long as the send has not started sending, you can easily cancel a scheduled send by following these steps:
- Go to Messages -> Send Status
- Highlight the message you'd like to cancel, and then click Cancel Send
- You'll see a message saying "Are you sure you want to cancel the selected send?" To confirm that you'd like to cancel the send, click Yes.
- The Status column in the Send Status report should now show as "Canceled"
Note: If your send has already started sending, it cannot be canceled from this screen. After the message has been delivered to the inbox, you can redirect links or modify the view as webpage version of the message.