Definition: 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
Input: customer: Hello. 
 agent: Hello, how can I best support you today? 
 customer: I am Samuel Green. I want to change my existing reservation due to the change of my trip dates. Can you help me? 
 agent: We are here to help you. 
 customer: Thank you. 
 agent: Just give me a moment please. 
 customer: Sure. 
 agent: Sorry to say that there is no reservation found on your name. 
 customer: No problem. Thank you for your response. 
 agent: Thanks for connecting us, have a nice day.
Output:
no_reservation