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. 
 customer: I am Amy Thompson. 
 agent: How can I assist you? 
 customer: I need to change my existing reservation due to postpone of my event at Houston. 
 agent: Ok, please wait. 
 customer: Could you please help me? 
 agent: Sorry, no reservation found on your name to change. 
 customer: No problem, thank you for the information. 
 agent: Thank you for reaching us.
Output:
no_reservation