Hi Rita,

You can do this in 2.5 when you add a custom notification to your face to face session.

1. go to the face to face activity
2. under Face to face admin > notifications
3. add a new notification
4. add a time after the event that you want it to be sent
5. select 'no show'
6. write your custom letter
7. add manager copy if required

This will send a notification to all of your DNAs 

Thanks