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

customer: Hi. 
 agent: Hello. 
 customer: I am Stephen Lopez. 
 agent: How may I assist you at this moment? 
 customer: Owing to an emergency, I want to change my reservation. Can you please help me in that? 
 agent: Sure, I am glad to help you out. 
 customer: Thank you. 
 agent: Please give me a moment to check your reservation status. 
 customer: Ok. 
 agent: Sorry, we couldn't find any reservation on your name in our records. 
 customer: Ok, no problem. Thank you for your response. 
 agent: Thank you for reaching us.
no_reservation