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. 
 customer: I am Brandon harris. 
 agent: How can I assist you? 
 customer: I need to cancel my reservation, can you help me out please? 
 agent: Sure, please wait for a minute. Brandon, there is no reservation found with your details. 
 customer: That's ok, no problem. Thank you for your information. 
 agent: Thank you for contacting us.
Student:
no_reservation