Use Sbasic in your on form entry to retrieve all records with callback date equal to @date.

This way when you open the form each time it will display all records needing a call. If you think about it you can even add a field that checks to see if you called it yet today based on time and omit those. I used the zip code sample program in my application so it even knows the time zone, this way it does not present anyone to call before a certain time in each specific state. 

There are many ways to achieve this goal based on your specific needs. If you only want it when you open the application use on application programming, If it is needed only on form entry use on form entry programming, Maybe the cleanest would be add a command button named Still to call and have Sbasic code that runs who still needs to be called for the day each time the button is pressed regardless of on form or application opening.

I guess this is the beauty of Sesame, You dream, You think, You get.

As long as you know what exactly you want to do there is most likely ways to do it using Sesame.