You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I would like to change my existing reservation due to some problem, can you please help me in this intent?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can I have your name please for checking your reservation status?

USER: Sure, my name is James Gonzalez.

ASSISTANT: Ok, please wait a moment and I will check your reservation status.

USER: Sure, take your time.

ASSISTANT: Sorry James Gonzalez, no reservation has found under your name to change.

USER: Ok, no problem. Thank you for your appreciable service.

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

USER: Most welcome.