Witz, here are the steps:
1. Select the message you want to delete
2. Look for the Actions option in the menu bar.
3. From the Actions list, choose one of the following options:
- If you want to just remove the message, select Recall This Message
- If you want to replace the message with a different one, select Replace This Message, and follow the on-screen prompts.
If the receiver has not yet opened your message, it will be removed from his inbox. You will get a notification saying something like "Message Recall Success"
If the received has already opened your message, he will get a note saying something like "Witzend is attempting to recall this message". And you will get a notification saying "Message Recall Failure".
If your boss has a habit of not checking his e-mail regularly you might be in luck. If he checks it but doesn't really read it, I wouldn't use this feature as it would just call attention to the message you're trying to recall.
Sending many hugs.
Trinity