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 assist you? 
 customer: I would like to cancel my recent reservation because my trip dates are got postponed, can you help me? 
 agent: Sure, I can help you with that. May I know your good name please? 
 customer: Anna Rodriguez here. 
 agent: Ok, please wait for a while. 
 customer: Sure. 
 agent: Anna Rodriguez, there is no active reservation found under your name to do cancellation. 
 customer: That's ok, thank you for checking. 
 agent: Thank you for choosing us.
no_reservation