If you’ve scheduled an event to be delivered in the future, you can cancel it using the cancelEvent() instance method, passing in the ID of the event you want to cancel. This will prevent any jobs listening for that event from being triggered. 
// Sending an event that will be delivered in 24 hours
const event = await client.sendEvent(
  {
    id: "event_12345",
    name: "my.event",
    payload: {
      foo: "bar",
    },
  },
  {
    deliverAt: new Date(Date.now() + 1000 * 60 * 60 * 24), // deliver in 24 hours
  }
);

// Sometime later, cancel the event by ID
await client.cancelEvent(event.id);
Cancelling an event after it has already triggered a job run does not cancel the job run. Cancelling events only prevent the event from triggering future job runs.