You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you now?

USER: Your agency have booked a ticket with wrong dates, can you help me in changing my reservation?

ASSISTANT: Sorry, may I know your name please?

USER: Myself David Martinez.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry David, there is no reservation found on your name.

USER: No problem, thanks for checking.

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