Instructions: 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
Input: customer: Hello. 
 agent: Hello. How may I help you? 
 customer: I am Matthew Parker. 
 agent: Matthew nice to meet you. 
 customer: Due to some reasons, my trip has been postponed. Can you change my reservation. 
 agent: Actually, there is no previous reservation found on your name. 
 customer: It's ok. 
 agent: Thank you for reaching us. 
 customer: Thank you for your help.
Output:
no_reservation