You will be given a definition of a task first, then some input of the task.
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: Hello. I am Barbara Walker. 
 agent: Hello. How may I assist you? 
 customer: I need to cancel my recent reservation, as I am suddenly fallen sick. Please help me in cancelling? 
 agent: Sure, we are here to help you. Please, stay online. I will check the previous list and revert to you. 
 customer: Ok. 
 agent: I have found a reservation on your name. Shall I cancel it? 
 customer: Ok, please cancel it. 
 agent: Your reservation has been cancelled. 
 customer: Thank you for your help. 
 agent: Thank you for reaching us, have a good day.
Output:
cancel