You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you now?

USER: I am Christopher Lopez. I am willing to change my travel dates in the past ticket, can you please help me in changing?

ASSISTANT: Sure Christopher Lopez, I will help you with that.

USER: Thank you for considering my request.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Ok, take your time.

ASSISTANT: Sorry Christopher Lopez, no reservation has found under your name.

USER: It's ok, thank you for searching.

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

USER: You are welcome.