Following Up on Update Requests

We have a sheet that contains a list of tasks. When a task (row) is supposed to be completed, an update request is sent to the person assigned (the request is triggered based on reaching a date that is entered in the row).

There is also a later date on which I want them to receive a reminder (if they haven't already done it). It is easy to create a second automated update request, but that leaves the first one hanging out there, and one of them will never be completed.

Is there a way to have that second request/reminder (and possibly a third) be a re-send of the original update request, so that we don't end up littered with update requests that never get completed?

Basically, I'm looking to automatically follow up on pending update requests without generating a new, separate request.

Thanks much.