Given the task definition and input, reply with output. 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, how may I assist you? 
 customer: Owing to emergency I want to cancel my recent reservation, can you help me with cancellation? 
 agent: Sure, I am here to help you. Please be online for a while, let me check your reservation status. Can you please tell me your name? 
 customer: Susan Anderson here. 
 agent: Sorry, I have not found any reservation under your name in our database. 
 customer: No problem, thank you. 
 agent: You are welcome and thank you for choosing us.
no_reservation