There are times when you have just sent an email and realise that it was supposed to be sent to someone else. Maybe you notice that you have missed adding a few important points to the email. You need not worry. Gmail lets you undo a sent message so that you can recall it right away. 

You will need to activate the Undo Send feature on your Gmail client. Here is how you can do is: 

· Go to your Gmail Settings 

· Scroll down to find the Undo Send feature. You should be able to find it under the General tab.

· Configure the send cancellation period from the drop-down. 

· Save your settings. You will need to scroll down and click on the Save Changes option to save your changes.