Q: 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. 
 agent: Hello. How can I provide assistance to you? 
 customer: I would like to change my reservation as I cannot go on that trip due to personal reasons, can you please help me with that? 
 agent: Can I know your name? 
 customer: Mary Thompson here. 
 agent: Give me a minute. 
 customer: Sure, take your time. 
 agent: Sorry, we couldn't find a reservation on your name to change. 
 customer: That's ok, thank you for checking. 
 agent: Thank you for choosing us.
A:
no_reservation