It looks like you would like to know if there is a way to stop a message from continuing to be sent once that message is sending.
In other words, you told the photocopier to print 100 copies but you realize after 1 or 2 that something is wrong. So, you want to stop the printing.
The answer is 'yes, this is possible'.
Just before we explain the 'how to', we want to be clear: some of the messages will continue to be sent even after you cancel the message (in the same way that even if you press 'Stop' or 'Cancel' on the photocopier, some copies continue to be printed).
As soon as you click Send, you will see that the message is sending.
At some point, you will see a Stop Now underneath your message. Click on this Stop Now.
A pop up box will appear so you can confirm your action. Clicking on Stop Now will end the message sending process.