You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I provide assistance to you?

USER: I would like to change my reservation as I cannot go on that trip due to personal reasons, can you please help me with that?

ASSISTANT: Can I know your name?

USER: Mary Thompson here.

ASSISTANT: Give me a minute.

USER: Sure, take your time.

ASSISTANT: Sorry, we couldn't find a reservation on your name to change.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.