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 can I assist you today? 
 customer: I am Barbara Perez, want to alter my existing reservation due to some personal issue. Please help me out with that. 
 agent: Sure, please wait for a moment. 
 customer: Ok. 
 agent: Sorry, there was no reservation found with your given name. 
 customer: It's ok, thank you for your help. 
 agent: Thank you for opting us.
no_reservation