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 may I aid you? 
 customer: I am planning to change an existing reservation, due to health issue. Can you please help me out to change my reservation? 
 agent: Sure, I am here to help you. 
 customer: Thank you. 
 agent: May I know your name to check your previous reservation status? 
 customer: I am Kathleen Rodriguez. 
 agent: Ok, please give me a moment. 
 customer: Sure, I will wait for your reply. 
 agent: Sorry, there is no reservation found on your name in our records to modify. 
 customer: That's fine, thank you you for your help. 
 agent: Thank you for reaching us.
no_reservation