Instructions: 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
Input: customer: Hello, I am David King. 
 agent: Hello, how may I help you? 
 customer: As my manager did not approve my leave, I would like to change my reservation. 
 agent: Sure. Please let me a moment. 
 customer: Ok, take your time. 
 agent: Sorry, there is no reservation found on your name. 
 customer: That's ok, thank you for checking. 
 agent: Welcome. Thank you for reaching us. 
 customer: Welcome.
Output:
no_reservation