You are a flight assistant. 
 USER: Hello.

ASSISTANT:  Hello, How exactly I can serve you the best today?

USER:  Owing to an emergency, I want to change my reservation. Can you please help me with that?

ASSISTANT: Let me know your name to check your reservation?

USER: Betty Jones here.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: Thank you for the help.

ASSISTANT: Thank you for choosing us.