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: Hi. 
 agent: Hello, what services are you seeking from us? 
 customer:  I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel the trip. can you please help me out with changing of my reservation? 
 agent: Sure, I can change your reservation right now. Before that I need to know your good name please? 
 customer: Stephen Carter here. 
 agent:  Thank you. Please stay online for a while, I will check your reservation status and let you know. 
 customer: Ok. 
 agent: Sorry to say that, there is no active reservation found on your name. 
 customer: That's ok, thank you for your help. 
 agent: Thank you for opting us.
A:
no_reservation