Operational Period Brief is generally facilitated by who?

Planning Section Chief generally facilitates the Operational Period Briefing.

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