You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is John Gonzalez.

ASSISTANT: How may I assist you today?

USER: Due to a sudden meeting, my family trip is postponed. Can you help me in changing the reservation?

ASSISTANT: Sure, please wait for a minute to check reservation details.

USER: Ok.

ASSISTANT: John Gonzalez sorry to tell you, I cannot find any reservation with your details.

USER: That's ok. Thank you for you time.

ASSISTANT: Thanks for contacting us, have a great day.