You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: Can you please help me in changing my reservation as my trip is postponed to other dates because of sudden health problem?

ASSISTANT: Sure, can I know you name?

USER: My name is Samuel Lopez.

ASSISTANT: I'm sorry, there are no reservations with your name.

USER: That's so sad. Thank you for your time.

ASSISTANT: Thank you, have a good day.