You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donald Robinson here.

ASSISTANT: How may I help you?

USER: Is this flight ticket booking agency?

ASSISTANT: Yes, what can I do for you?

USER: Me and my friends are planned for a hangout trip, but someone didn't manage with his leaves, so we want to extend our trip to some other dates, so could you please help me out with changing my reservation?

ASSISTANT: Sure, definitely I will help you.

USER: Thank you.

ASSISTANT: Donald, no reservation has been found on your name.

USER: Oh, I think the ticket was not booked properly while I am booking. Anyways, thank you for the information.

ASSISTANT: Thank you for approaching us.