Precocious cheeky behaviour in six year old grandaughter

My grandaughter is very clever, very pretty and very outgoing. And does she know it. Her behaviour is verging on embarrassing in public, and sometimes downright rude and disrespectful in private. Her parents worship her and take far too many photos. I am concerned she is turning into a monster. It’s not just me that thinks it, most of the family find her obnoxious. Is there anything I can do?