My new date is FEB. 27th not FEB 28th!!!!

Hi guys, I guess Dr. A is not available the 28th so February 27th it's official. I was authorized! I am worried about something though. Lois said that the insurance companies will not committ to telling patients that they will cover the surgery. I need to know. I don't want to be stuck with a high bill! What do i do?? I have Connecticare