What is an effective method for teaching a new behavior that involves balancing too much versus too little reinforcement?

The police of a resort town discovered that a well-known cat burglar was currently living in town under an assumed name. to try to catch her in the act of burglary, an undercover officer approached the burglar with a plan for a burglary. the undercover officer told the burglar that he knew who she was and that he had a plan to steal jewels from someone staying in one of the town's resorts. the burglar initially refused the offer; however, after lengthy cajoling, she finally agreed to the plan. as the time for the burglary drew near, the burglar had second thoughts. three hours before the theft was scheduled to take place, the burglar called the police and told them of the plan. she told them that she was not going to show up, but that her cohort (the undercover officer) would be there, and told them how to recognize the undercover officer. is the burglar guilty of conspiracy at common law?