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 can I help you? 
 customer: Elizabeth Clark here, please cancel my ticket, I have other works on those dates. 
 agent: Ok, please wait for a moment. 
 customer: Ok. 
 agent: There is no reservation found on your name. 
 customer: Ok, no issues, thank you for your clarification. 
 agent: Thank you for approaching us, have a nice day. You are welcome.
Student:
no_reservation