Directly Responsible Individual means a human individual who is accountable for a given Area Of Responsibility. A DRI is a single person, not a group of people. If there is a shift schedule, define each shift as a separate AOR (e.g. Tier 2 Mobile Support Escalations Weekdays 8am to 5pm Palo Alto time). If you are unsure who is the DRI, make the AOR more specific until the DRI is clear.