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? 
 customer: I am Ashley Lee. I want to cancel my reservation, due to my health issues. Could you help me in the cancellation? 
 agent: Sure, we are here to help you. Wait for some time. 
 customer: Sure. 
 agent: Thanks for waiting there is no reservations found on your name. 
 customer: Not an issue. Thank you. 
 agent: Thanks for choosing us.
no_reservation