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: Hello, I am Barbara Adams. 
 agent: Hello, how may I help you today? 
 customer: I need to fly Phoenix, could you please help me in booking my flight ticket from CLT to PHX? 
 agent: Sure, may I know your travel dates? 
 customer: My planned trip dates are 12/16 and 12/18. 
 agent: Do you need a connection in between your journey? 
 customer: I need a connecting flight. 
 agent: Ok, please wait for a while. 
 customer: Ok. 
 agent: Sorry, there were no flights found on your route. 
 customer: Ok, no issues. Thank you for your service. 
 agent: Thank you for reaching us.
Student:
no_flight