Once an alert is triggered, the home screen in your App will change to display an "I'm Ok" button at the bottom of the screen.
To cancel an alert, simply press "I'm Ok" This will return your app to ready mode. If the alert was dispatched to your circle, they will receive a text notifying them that you've cancelled the alert.
Failure to confirm "I'm Ok" after an alert can impact your ability to trigger future alerts and may also impact batter life.