Yeah, it's a tricky one and it'd probably depend on why you don't want to share your records with the new doctor but I'd probably say something like, "Sorry, but with all due respect, I'd rather not share those records because I didn't trust Doctor X's evaluation of my symptoms, etc." Because that's the only reason I can think of, at present, why I'd not want to share records. But just say whatever it is in a respectful way with no recrimination's or abusive language.