You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to change my existing reservation, as my exams got postponed. Can you please help me out with it?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Thank you, my name is Catherine Collins.

ASSISTANT: Please allow me a moment.

USER: Ok, sure.

ASSISTANT: There is no reservation found under your name in our data base.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thank you for contacting us.