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
Input: customer: Hello,. 
 agent: Hello, how may I help you? 
 customer: I am Mark Lewis, I want to change my existing reservation as my company meeting got postponed. 
 agent: Sure Mark, please wait a moment I'll check the details of your reservation. 
 customer: Sure. 
 agent: Sorry for the inconvenience, there is no reservation found on your name. 
 customer: Ok, no problem . Thank you for the information. 
 agent: Thank you for approaching us. Have a nice day!.
Output:
no_reservation