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: Hi. I am Angela Nelson. 
 agent: Hello, what kind of assistance are you looking for? 
 customer: Usually I prefer a connecting flight, but unfortunately my friend has already reserved my ticket with a direct flight. So, I want to change it.Can you help me? 
 agent: Sure, please wait. 
 customer: Thank you. 
 agent: Sorry, we couldn't find any reservation on your name to change. 
 customer: No issue. Thank you for the information. 
 agent: Thank you for reaching us.
Student:
no_reservation