Given the task definition and input, reply with output. 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: Hello. 
 agent: Hello, how can I help you today? 
 customer: Emily Anderson here. I would like to travel from EWR to meet my brother who was staying in BOS, can you help me to find a flight? 
 agent: Sure, we are here to help you. Can you share me your travelling dates? 
 customer: Thank you. My travelling dates are Nov, 22 and Nov, 24. 
 agent: Do you need any halt in between your journey? 
 customer: Yes, I need a halt between journey. 
 agent: Ok, wait for some time I will check and get back to you. 
 customer: Sure. 
 agent: Thanks for waiting there are no flights found on your details. 
 customer: That's fine, thanks for your information. 
 agent: Thanks for approaching us.
no_flight