Given the task definition and input, reply with output. 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. 
 agent: Hello, how may I oblige you today? 
 customer:  I would like to cancel my flight reservation as my trip got postponed, can you please help me? 
 agent: Sure, may I know your good name? 
 customer: Paul King here. 
 agent: We found a reservation on your name, shall I proceed? 
 customer: Please proceed. 
 agent: Your reservation has been cancelled successfully. 
 customer: Thank you for the help. 
 agent: Thank you for reaching us.
cancel