Problem
You can't close a work order because it says you need a managed technician assigned.
Solution
In order to complete a work order in ServiceTitan, a managed technician timesheet must be added to the work order. Adjust the invoice Splits and assign a managed technician to the work order to close it out.
Adjust splits of the invoice
Go to the invoice page of the work order you're trying to close out.
Click Adjust Splits.
Click Add another and add a managed technician from the dropdown list.
In the Sold Hours (%) section, assign 100% of the splits to the managed technician you added.

When you're finished, click Save.
Assign a managed technician to the work order
If adjusting splits doesn't allow you to close the work order, proceed to assign the managed technician directly to the appointment.
Go to the work order.
In the Scheduled Appointments section, Assign a managed technician. Ensure the technician is clocked in or available to be assigned.
Click Dispatch > Arrive.
Go to the Work Order Actions and select Complete Work Order.
Update the invoice details and click Save.
For more, see Managed technicians and non-managed technicians.
Reschedule an appointment to next year
Note: The system expects an active managed technician with a timesheet to close, or reschedule a non-$0 work order to a future date.
In ServiceTitan, go to the appointment you want to move.
Check if a managed technician is assigned to the appointment.
If no technician is assigned, assign a managed technician.
Try to reschedule the appointment to next year again.
If the error persists, ensure all required fields are filled out.