You would be assigned to a health care team called a Patient Aligned Care Team or PACT. Your team would be made up of you, those who support you , and your health care providers.
could I change my main doctor if I didn't like the one I got assigned to?
You will need to talk to your health care team leader or to the patient advocate at your VA medical center to take care of that
is there a backup plan for  when someone from the pact team is missing?