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. Nancy Perez here. 
 agent: Hello, how can I assist you now? 
 customer: I am planning to visit Boston university to collect my graduation certificate. I will fly from LAX - BOS. 
 agent: Ok, may I know the travelling dates please? 
 customer: I will be travelling from 03/30 and end my journey on 04/01. 
 agent: Please wait for a while, I will check the details and get back to you. 
 customer: Ok. 
 agent: Sorry, there are no flights found on your requested dates. 
 customer: Not a problem. 
 agent: Do you have any other dates to travel? 
 customer: It is ok. Thank you. 
 agent: Thank you for approaching us, have a nice day.
no_flight