You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What help is required from our agency?

USER: I have booked a ticket with wrong dates. Can you please help me for changing the existing reservation?

ASSISTANT: Sure, I will help you.

USER: Thank you for considering my query.

ASSISTANT: Please let me know your name to search the reservation status?

USER: Sure, my previous reservation is on the name of Dennis White.

ASSISTANT: Give me a moment please.

USER: Sure, take your time.

ASSISTANT: Sorry White, there is no reservation found on your name in our database.

USER: No problem, I will search another alternative way. Thank you for your service.

ASSISTANT: Thank you for approaching us.