We found one through our pediatrician (who gave us a short list of PhD CBTs). I don't know what area you're in but I can share her name if you're in the DFW area. She actually worked at a prep school but had a limited number of spots for private practice sessions outside of school hours. She was AMAZING and made a big difference for our DD2 (and us as well - DH did a session with her privately). She didn't want to guarantee that it would take X number of sessions so we paid for each session as we went. I think we went about once a month-ish for about a year. She would start each session with just a couple minutes of a parent and DD together to explain what she hoped to accomplish and to get everyone comfortable and then DD would talk with her privately. She'd end each session by summarizing for the parent what they accomplished and what we should work on at home, and she would share specifics as DD allowed (ie, she made sure in advance "is this something I can share with your mom when we're done?". And then DH saw her separately once as well because he was struggling the most with DD
We even called her while we were on vacation when DD had some concerning behavior, and she coached us through what to do in that moment.
We were EXTREMELY lucky that she was a good fit for DD upon first meeting. EXTREMELY.