Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hi. 
 agent: Hello, how can I help you? 
 customer: Could you please book a flight ticket from PHL to BOS? 
 agent: Sure, may I know the travelling dates? 
 customer: My trip dates are Feb 06 and Feb 08. 
 agent: Do you have any connection limit? 
 customer: I need a connecting flight. 
 agent: Are there any other requirements? 
 customer: No. 
 agent: May I know your name? 
 customer: I am Angela Garcia. 
 agent: Please wait a minute. 
 customer: Sure. 
 agent: Sorry, no flights found with your preferable dates. 
 customer: No problem, thank you. 
 agent: Thank you for opting us.
Student:
no_flight