How does the "Alert me if a group stops reporting data" setting work?

Hi,

I have a configuration similar to the one described in the documentation with grouping alerts by host.name.

Now, one of my hosts, which was found before, was replaced by a new host, but since this change, I get NO DATA alerts for that old host.

How long will these alerts be created or how could I stop checking for that old host?

Kind regards,
Norbert