Given the task definition and input, reply with output. 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: Hi. 
 agent: Hello, May I know what kind of service you are looking for? 
 customer: I have to change my travel airport codes because I have given a airport code which is far to my current location. So, I need your help. Will you please help me in changing the details? 
 agent: Sure, I can change your reservation right now. Before that I need to know your good name please? 
 customer: Nancy Jackson here. 
 agent: Ok, wait for some time I will check the reservation on your name and get back to you. 
 customer: Ok. 
 agent: We are sorry to say that, there is no active reservation found on your name. 
 customer: No issue, Thank you for the information. 
 agent: Thanks for approaching us.
no_reservation