Google’s Gmail provides an option to let user have chance to withdraw an email which is sent out in a limited time.
1: Sign in your Gmail, Click the gear icon on the top right corner, then select Settings item:
2: On the Gmail Settings page, just in the General tab page, Check on Enable Undo Send,and give a Send cancellation period which is up to 30 seconds (There are 5, 10, 20 and 30 seconds options in the dropdown list):
3: Scroll down to the very bottom of the settings page, click Save changes button:
4: Now you can start to use the Gmail Undo feature (Withdraw email).
For a test you can try to send an email to yourself now. After you clicked to send out, you can see a message with 2 link buttons on the top of Gmail window. Click the Undo link button to withdraw the email which you just sent out.