Definition: 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 can I help you? 
 customer: I want to change my reservation, due to heavy rainfall in Seattle, can you help me in changing the reservation? 
 agent: Sure, May I know your name? 
 customer: I am Thomas Taylor. 
 agent: Sorry, No reservation found on your name. 
 customer: That's ok, thank you for your information. 
 agent: Thank you for opting us.
Output:
no_reservation