In this task, you are given a conversation between a flight agent and the customer. You are given 4 options and you need to select the goal of the conversation. It is provided as part of customer's context, which has to be one of the following: `book`: Make a new reservation, `cancel`: Cancel an existing reservation, `no_flight`: No flight found for the customer's preference, `no_reservation`: No reservation / No change / No cancellation was made in the conversation, mostly enquiring details

customer: Hi, I'm Janet Campbell. 
 agent: Hello, how may I assist you? 
 customer: I would appreciate if you can cancel my ticket reservation. 
 agent: Sure. Wait for a moment, I will check the details and get back to you. Unfortunately, no reservation found on your details. 
 customer: Thanks for your information. 
 agent: Thanks for contacting us.
no_reservation