You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I will be changing my travel dates in my previous reservation, can you help me please?

ASSISTANT: Sure, may I know name please to check the reservation status?

USER: Sure, my name is Karen Adams.

ASSISTANT: Karen, there is no reservation found with your details.

USER: Oh! That's very sad to hear from you. Anyways, thank you for checking for my reservation.

ASSISTANT: Thank you for choosing us, have a good day.

USER: You are most welcome.