You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I do for you at this moment?

USER: I want to reschedule my trip dates of my recent reservation as my get together party got postponed. Can you help me in changing the reservation made by name Margaret White?

ASSISTANT: Sure, please wait for few minutes.

USER: Ok.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: That's Ok, thanks for your assistance.

ASSISTANT: Thank you for reaching us.