You will be given a definition of a task first, then some input of the task.
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. What service do you need from our agency? 
 customer: I would like to change my existing reservation, could you please help me? 
 agent: Sure, I will help you to change the ticket details. 
 customer: Thank you. 
 agent: Could you please mention your respective name? 
 customer: My name is Joshua Clark. 
 agent: Ok, please give me a couple of seconds to check the ticket status. 
 customer: Sure, I will wait for your response. 
 agent: I have not found any active reservation with your name in our system data to change the ticket details. Sorry for the trouble. 
 customer: No issues. Thank you for checking. 
 agent: That's my pleasure. Thank you for reaching us.
Output:
no_reservation