How do I go about switching my son's pediatrician?

I've recently had some concerns about my 3 year old son's pediatrician. I've been going to her since he was born, but lately I'm not happy with her. She is very laid back, which can be good, but she's missed a few things recently.This has been an ongoing problem, which I've tried to overlook because I didn't want to be superficial, but she is very overweight and just doesn't look healthy. She often has dirty hair and her nails don't look properly groomed. I've been trying to look past all of this,but last week she diagnosed my son with something and when I spoke to his ENT about it, he told me that what she said was factually incorrect and that he was wrongly diagnosed (nothing serious). It just made me question whether or not she really knows her stuff. All this said, I think I need to switch doctors. I just don't know how to go about it. I don't want to have an awkward conversation with her. I can't tell her that I don't want to take my son to her because she doesn't look healthy and isn't a good doctor. She's a nice lady, but I need someone else to care for my son's health. How do I get my son's charts if I don't tell them I'm switching doctors? I want to make this as painless as possible, but I think it's going to be awkward. Any advice?