Detailed 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
Q: customer: Hello. 
 agent: Hello, how can I be your helping hand? 
 customer: I am Carol Lewis. My family tour trip got postponed, so I want to change an existing reservation. 
 agent: Ok. 
 customer: Could you help me in changing the reservation? 
 agent: Sure, I will help you. Please wait for a moment, I will check your reservation. 
 customer: Sure. 
 agent: Thank you for being patience, there is no reservation found on your name. 
 customer: Not an issue. Thank you. 
 agent: Thank you for reaching us.
A:
no_reservation