Synago supports the concept of silent rescheduling, meaning that users can be assigned and reassigned days to attend during a week, while the majority of users will not be notified about the changes.
David usually has time to attend service twice a week, and that usually works out fine.
Imagine the plan this week looks like this. Only David and Shmuel are shown, as the rest attending is not important, only whether or not a minyan is guaranteed.
David receives an email that tells him he needs to work overtime, and will not be able to make it for service on Sunday.
He also doesn’t wear a kippah at work.
David quickly sends a text message to Synago, asking to cancel his attendance this Sunday.
Synago now has to remove David from attendance Sunday. But in this example, he was exactly the 10th person assigned, and thus the minyan is no longer guaranteed. What should Synago do now?
Synago looks around for alternatives. It sees that Monday does not yet have a minyan, so Shmuel could safely be moved to Sunday, without interfering with any guaranteed minyan services.
Let’s hope Shmuel is not busy.
Synago automatically dispatches a text message to Shmuels phone.
Synago also understands derivations of the affirmative. So even though it asked for a “yes”, Shmuel got away with saying “OK”.
Shmuel was luckily not doing anything, so he was able to cover for David. Synago then moves Shmuels commitment to Sunday, and none of the other 9 people attending had to be disturbed.
In the real world, there would probably have been more candidates than Shmuel, so Synago would reach out to those as well. Synago will attempt to re-ensure a minyan continuously, until about a day before Sunday, or until someone says yes.
If Synago has to give up, the remaining 9 people will receive a text message informing them, that guaranteed minyan is no longer possible.