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. 
 agent: Hello, how may I oblige you today? 
 customer: Can you please help me in changing my previous reservation? 
 agent: Sure, may I know your good name? 
 customer: Myself Donald Edwards. 
 agent: Ok, please wait for a minute. 
 customer: Sure. 
 agent: Thanks for waiting, there is no active reservation found on your name. 
 customer: It's ok, thank you. 
 agent: Thank you for choosing us.
Student:
no_reservation