To force a Patch service into an 811 (reboot) add the following syntax to the Patch service.

Note: Using MS-KB4516655 as the example service to force a reboot.

Navigate to:

PRIMARY.PATCHMGR.ZSERVICE.MS-KB4516655 /reboot and double click the reboot variable.

Enter the value: 

AI=IQ 

NOTE: Setting a reboot flag to 811 will not stop other Patch services from installing during the same patch connect.