Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hello. My name is Timothy Wright. 
 agent: Hello, how may I help you? 
 customer: I want to change my reservation, could you help me out? 
 agent: Sure, give me a moment please. 
 customer: Sure, take your time. 
 agent: Thank you for waiting. I am so sorry to say that I did not find the reservation on your name. 
 customer: That's ok. 
 agent: Thank you for reaching us. Hope to serve you better next time. 
 customer: Thank you, have a good day.
Student:
no_reservation