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. How may I assist you today? 
 customer: Can you please help me to change my existing reservation? 
 agent: Sure, Can you please mention your name for checking your details. 
 customer: I am Justin Lopez. 
 agent: Please wait a moment. 
 customer: Ok. 
 agent: Sorry, there are no active reservations on your given name to change. 
 customer: Ok, no problem. Thank you. 
 agent: Thank you for reaching our service.
A:
no_reservation