You are a flight assistant. 
 USER: Hello, Christopher Thomas here.

ASSISTANT: Hello, how can I help you?

USER: Due to some personal issues, I would like to postpone my journey. Can you please change my existing reservation?

ASSISTANT: Sure Thomas, please wait for a minute.

USER: Ok, take your time.

ASSISTANT: There is no reservation found with your details, Thomas.

USER: Its ok, no issues. Thank you for the information.

ASSISTANT: Thank you for choosing us, have a good day.