You will need a PA from insurance and your doctor's office is who will need to contact insurance to get it. They will have to give a reason for the change. Patient's can't do it themselves. I've had to go through this process many times including moving to 6 weeks when I was on Entyvio.
With the biologics every change has to get a new PA from insurance. You would be stuck with the bill without getting the approval. The customer service reps we talk to when we call insurance don't know a lot about
infused medications.
Contact your doctor's office and get them moving