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 help you? 
 customer: My name is Robert Lopez. Can you please help me in cancel my reservation. 
 agent: Sure, wait a minute. 
 customer: Ok. 
 agent: We found your reservation and it has been cancelled. 
 customer: Thank you for the help. 
 agent: Thank you for choosing us.
Student:
cancel