You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Jack Collins.

ASSISTANT: How may I help you?

USER: Actually, I booked a ticket to NYC for a concert but due to bad weather, my trip is postponed.

ASSISTANT: Ok, so would you like me to change your existing reservation?

USER: Yes, can you help me out?

ASSISTANT: Yes, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, I could not find any ticket booked with your name.

USER: That's ok. Thank you, have a good day.

ASSISTANT: Thank you, have a nice day.