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. 
 customer: I am Melissa Hall. 
 agent: How can I help you today? 
 customer: I need your assistance in cancelling my recent reservation, can you help me with it? 
 agent: Sure, I will help you to cancel your reservation. 
 customer: Thank you. 
 agent: Please allow me a moment. 
 customer: Sure. 
 agent: Sorry, no reservation found on your name to cancel your reservation. 
 customer: That's fine, thank you for your information. 
 agent: Welcome, have a nice day.
no_reservation