WHEN do I get Doc to send in letter to insurance?

Hi there, I was wondering after talking to Cigna, when do I have my Dr (pcp) send in the initial letter that he says that I am requesting WLS?    Cigna says for him not to send it until I have finished my 6 month superv. diet.... that is the first time I heard of that. I thought they were to get the letter at the onset.... Then I can find out if I even have a chance of approval if after that I can document the  6 mos. of dr. diet. Maybe I have missed something here. Thanks for any input, as I want this to go smoothly.

You don't have to wait.  He can send it in now, and if they deny it you can appeal or do the diet.  You don't have to wait the 6 months.