You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am John Wilson.

ASSISTANT: How may I help you?

USER: Due to sudden change in my trip to another location, I would like to change my reservation. Can you please help me out?

ASSISTANT: Sure, please give me a moment to check your previous booking.

USER: Ok.

ASSISTANT: Thank you for your patience. I am sorry to say that there is no reservation found for the name which you have mentioned.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us, have a nice day.