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 help you? 
 customer: As my meeting got postponed with my client, can you please help me in changing my existing reservation? 
 agent: Sure, we are happy to help you. Can you please let me know your good name? 
 customer: I am Barbara Jones. 
 agent: Sorry, there is no active reservation on your name in our records. 
 customer: Ok, no issues. Thank you for the information. 
 agent: Thank you for availing us.
no_reservation