Cancel a stack update
After a stack update has begun, you can cancel the stack update if the stack is still in
      the UPDATE_IN_PROGRESS state. After an update has finished, you can't cancel it.
      You can, however, update a stack again with any previous settings.
If you cancel a stack update, the stack is rolled back to the stack configuration that existed before initiating the stack update.
To cancel a stack update (console)
- Sign in to the AWS Management Console and open the AWS CloudFormation console at https://console.aws.amazon.com/cloudformation - . 
- 
            On the navigation bar at the top of the screen, choose the AWS Region where the stack is located. 
- 
            On the Stacks page, choose the stack that's currently being updated. Its status must be UPDATE_IN_PROGRESS.
- 
            Choose Stack actions and then Cancel update stack. 
- 
            To continue canceling the update, choose Cancel update. Otherwise, choose Cancel to resume the update. 
The stack proceeds to the UPDATE_ROLLBACK_IN_PROGRESS state. After the
         update cancellation is complete, the stack is set to
         UPDATE_ROLLBACK_COMPLETE.
To cancel a stack update (AWS CLI)
Use the command cancel-update-stack to cancel an update. For more information, see Cancel a stack update.