Operational Period Brief is generally facilitated by who?

The Operational Period Briefing is generally facilitated by the Planning Section Chief

The Planning Section is responsible for collecting, evaluating, and disseminating tactical information related to the incident. By leading the Operational Period Briefing, the Planning Section Chief ensures that the flow of information is consistent and that all operational decisions and assignments are based on the most current and accurate information available. 

Source: https://training.fema.gov/emiweb/is/is200c/english/instructor%20guide/is0200c%20ig.pdf