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: Hello. 
 agent: Hello, how can I help you today? 
 customer: I need to change my recent reservation due to my exams, can you help me in doing that? 
 agent: Sure, I am here to help you with that. 
 customer: Thank you. 
 agent: Can you please share me your name? 
 customer: I am Mary Anderson. 
 agent: Sorry, no reservation found on your name to change your reservation. 
 customer: Ok, no issues. Thank you for the information. 
 agent: Thank you for reaching us, have a nice day.
no_reservation