Detailed Instructions: 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
Problem:customer: Hello. 
 agent: Hello, how may I help you? 
 customer: Meeting a family friend got postponed, will you help me to change my existing reservation? 
 agent: Sure, can I know your name? 
 customer: Sure, my name is Sandra Clark. 
 agent: Ok, please hold on. 
 customer: Sure. 
 agent: Sorry, no reservation found on given name. 
 customer: Ok, thank you for your information. 
 agent: Thank you for reaching us.
Solution:
no_reservation