The practical signal
A list of old phone numbers or vague instructions such as "call someone" does not make a technical report usable. The reporting room must know what is allowed within which limits.
Emergency room monitoring works only when an alarm notification leads to an pre-arranged, current and executable action.

A list of old phone numbers or vague instructions such as "call someone" does not make a technical report usable. The reporting room must know what is allowed within which limits.
Determine types of notifications, desired verification, contact sequence, available keyholders, and situations where immediate escalation is required. Check who may report changes.
Write a short, concrete action plan that aligns with the location, opening hours, and authorities. Keep personal data limited to what level of follow-up is necessary.
Discuss the plan with the involved parties and carry out a test report. Record who responded, where the delay occurred, and when contact information will be rechecked.
Actions depend on the contract, the report and the agreed protocol.
With every relevant change in staff or contact and periodically as a regular routine.