Hi Dect,
maybe you can elaborate a bit more because it is difficult to understand what you want to do.
In case you mean SBO alerts ( SQL queries sending a result to an user ) - you don't need an addon ( use SBO clients "Alerts Managment" ).
If you want to add a user defined form and check if a date is passed and if so show a message : use UI API method MessageBox.Show("Drivers license expired"). Or you can use the DI API MessageService to send a message to another user.
regards,
Maik