Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hello. I am Emily Walker. 
 agent: Hello. What help do you require from us? 
 customer: I want to change my existing reservation, due to financial issues. 
 agent: Sure, I will check your previous ticket. Sorry to tell you that, I didn't found any reservation on your name to modify. 
 customer: That's ok, thank you for your help. 
 agent: You are most welcome. Thank you for consulting us. Have a good day.
Student:
no_reservation