You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What service that you are looking from our agency?

USER: I am Mark Smith.

ASSISTANT: Nice meeting you Mark Smith.

USER: Thanks, nice to meet you too. I want to change my travel dates in my previous reservation, can you please help me with that?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

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

USER: Ok.

ASSISTANT: We regret that, there is no reservation with your name in our records.

USER: Oh! It's ok no problem, may be I am not booked my ticket properly at that time. Thank you for your service.

ASSISTANT: Thank you for approaching us, have a great day.