You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I am planning to change the travel dates in the past ticket, can you please help me to do that?

ASSISTANT: Sure, I can help you. May I know your name?

USER: Thank you. I am Christopher Hill.

ASSISTANT: Please give me a moment to check your ticket status.

USER: Ok, take your time. I will wait for your response.

ASSISTANT: Sorry Christopher Hill, no reservation is available by your name.

USER: It's ok, not a problem with that. Thank you for checking my ticket status.

ASSISTANT: Thank you for approaching us.