You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Amanda Parker. I want to change my existing reservation due to bad weather condition, can you please help me in that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: There is a reservation found under your name to change, can you please mention your dates of travel?

USER: I want to fly on 10/21, return on 10/23.

ASSISTANT: Ok, may I know your airports codes please?

USER: My source and destination airport codes are TX - DFW and PA - PHL.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Parker, there is no flight found as per your travelling details.

USER: No problem, thank you.

ASSISTANT: You are welcome, have a safe flight.