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, I am Susan Robinson. 
 agent: Hello, how can I assist you? 
 customer: Can you please help me with changing the reservation? 
 agent: Sure, we will help you. 
 customer: Ok. 
 agent: Please wait a moment, I will check your details and get back to you. 
 customer: Ok. 
 agent: Thank you for waiting, sorry to inform you that there is no reservation exist on your name to do modification. 
 customer: Ok, no issues. Thanks for the help. 
 agent: Thank you for contacting us.
A:
no_reservation