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. This is Dennis Evans. 
 agent: Hello, How can I serve you? 
 customer: I am planning to visit Kennedy park, which is located in Oakland CA-OAK.So I would like to fly from Seattle. Can you please aid me in booking a flight ticket? 
 agent: Sure, May I know the source code? 
 customer: My source code is WA-SEA. 
 agent: Please help me with your travel dates. 
 customer: My travel dates are 08/24 and 08/26. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Sorry, No flights found with your chosen dates. 
 customer: Ok, no issues. Thank you. 
 agent: Thank you for availing us.
no_flight