DAV property name: http://schemas.microsoft.com/mapi/reminderset

Data type: PtypBoolean ([MS-OXCDATA] section

The PidLidReminderSet property ([MS-OXORMDR] section gets or sets a calculated value that indicates whether a reminder is set on the object. True if a reminder is set on the object; otherwise, false.

For more details about the PidLidReminderSet property, see [MS-OXPROPS] section 2.222.