hello,
filtered views are views and cannot be updated. It is also not recommended to do direct updates on database.
you could write a console application to open the appointment. Modify the appointment and close it.
if there are only few appointment, you could do it through a workflow.
1. Create an ondemand workflow to open a closed appointment.
2. Run this workflow on the appointment.
3. Make the party change, close the appointment.
regards,
Jithesh