question on approval letters

When you are trying to get approved for the surgery who writes the so called plea letter, Doctor or myself? That part has always confused me. At work we have heard our insurance is changing and it will be United Healthcare or GHP. Any words of wisdom? If so please email me or on this message board. Thanks

Your primary care doctor needs to write the letter including any medical problems you have due to being overweight. Also, I have United Healthcare and they were great about approval. I got my approval in a little over a week. Good luck.